Autonomous surface cleaning robot for wet and dry cleaning

ABSTRACT

An autonomous floor cleaning robot includes a transport drive and control system arranged for autonomous movement of the robot over a floor for performing cleaning operations. The robot chassis carries a first cleaning zone comprising cleaning elements arranged to suction loose particulates up from the cleaning surface and a second cleaning zone comprising cleaning elements arraigned to apply a cleaning fluid onto the surface and to thereafter collect the cleaning fluid up from the surface after it has been used to clean the surface. The robot chassis carries a supply of cleaning fluid and a waste container for storing waste materials collected up from the cleaning surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of, U.S.application Ser. No. 11/359,961, the disclosure of which is hereinincorporated by reference in its entirety. U.S. application Ser. No.11/359,961 claims priority under 35 U.S.C. §119(e) to U.S. ProvisionalApplication Ser. No. 60/654,838, the entire disclosure of which isherein incorporated by reference it its entirety. U.S. application Ser.No. 11/359,961 also claims priority under 35 U.S.C. §120 to U.S.application Ser. No. 11/134,212, U.S. application Ser. No. 11/134,213,U.S. application Ser. No. 11/133,796, U.S. application Ser. No.11/207,574, U.S. application Ser. No. 11/207,575, and U.S. applicationSer. No. 11/207,620, the entire disclosures of which are hereinincorporated by reference in their entireties. This application relatesto and herein incorporates by reference in their entireties thedisclosure of the application entitled “Autonomous Surface CleaningRobot for Wet and Dry Cleaning,” by Zeigler et al., filed on even dateherewith; the application entitled “Autonomous Surface Cleaning Robotfor Dry Cleaning,” by Morse et al., filed on even date herewith; theapplication entitled “Autonomous Surface Cleaning Robot for WetCleaning,” by Konandreas et al., filed on even date herewith, theapplication entitled “Autonomous Surface Cleaning Robot for Wet and DryCleaning,” by Ziegler et al., filed on even date herewith, and theapplication entitled “Autonomous Surface Cleaning Robot for Wet and DryCleaning,” by Ziegler et al., filed on even date herewith.

BACKGROUND OF THE INVENTION

The present invention relates to cleaning devices, and moreparticularly, to an autonomous surface cleaning robot.

DESCRIPTION OF RELATED ART

Autonomous robot floor cleaning devices having a low enough end userprice to penetrate the home floor cleaning market are known in the art.For example, and U.S. Pat. No. 6,883,201 by Jones et al. entitledAutonomous Floor Cleaning Robot, the disclosure of which is hereinincorporated by reference it its entirety, discloses an autonomousrobot. The robot disclosed therein includes a chassis, a battery powersubsystem, a motive drive subsystem operative to propel the autonomousfloor cleaning robot over a floor surface for cleaning operations, acommand and control subsystem operative to control the cleaningoperations and the motive subsystem, a rotating brush assembly forsweeping up or collecting loose particulates from the surface, a vacuumsubsystem for suctioning up or collecting loose particulates on thesurface, and a removable debris receptacle for collecting theparticulates and storing the loose particulates on the robot duringoperation. Models similar to the device disclosed in the '201 patent arecommercially marketed by IROBOT CORPORATION under the trade names ROOMBARED and ROOMBA DISCOVERY. These devices are operable to clean hard floorsurfaces, e.g. bare floors, as well as carpeted floors, and to freelymove from one surface type to the other unattended and withoutinterrupting the cleaning process.

In particular, the '201 patent describes a first cleaning zoneconfigured to collect loose particulates in a receptacle. The firstcleaning zone includes a pair of counter-rotating brushes engaging thesurface to be cleaned. The counter-rotating brushes are configured withbrush bristles that move at an angular velocity with respect to floorsurface as the robot is transported over the surface in a forwardtransport direction. The angular movement of the brush bristles withrespect to the floor surface tends to flick loose particulates laying onthe surface into the receptacle which is arranged to receive flickedparticulates.

The '201 patent further describes a second cleaning zone configured tocollect loose particulates in the receptacle and positioned aft of thefirst cleaning zone such that the second cleaning zone performs a secondcleaning of the surface as the robot is transported over the surface inthe forward direction. The second cleaning zone includes a vacuum deviceconfigured to suction up any remaining particulates and deposit theminto the receptacle.

In other examples, home use autonomous cleaning devices are disclosed ineach of U.S. Pat. No. 6,748,297, and U.S. Patent Application PublicationNo. 2003/0192144, both by Song et al. and both assigned to SamsungGwangu Electronics Co. The disclosures of the '297 patent and '144published application are herein incorporated by reference it theirentireties. In these examples, autonomous cleaning robots are configuredwith similar cleaning elements that utilize rotating brushes and avacuum device to flick and suction up loose particulates and depositthem in a receptacle.

While each of the above examples provide affordable autonomous floorclearing robots for collecting loose particulates, there is heretoforeno teaching of an affordable autonomous floor cleaning robot forapplying a cleaning fluid onto the floor to wet clean floors in thehome. A need exists in the art for such a device and that need isaddressed by the present invention, the various functions, features, andbenefits thereof described in more detail herein.

Wet floor cleaning in the home has long been done manually using a wetmop or sponge attached to the end of a handle. The mop or sponge isdipped into a container filled with a cleaning fluid, to absorb anamount of the cleaning fluid in the mop or sponge, and then moved overthe surface to apply a cleaning fluid onto the surface. The cleaningfluid interacts with contaminants on the surface and may dissolve orotherwise emulsify contaminants into the cleaning fluid. The cleaningfluid is therefore transformed into a waste liquid that includes thecleaning fluid and contaminants held in suspension within the cleaningfluid. Thereafter, the sponge or mop is used to absorb the waste liquidfrom the surface. While clean water is somewhat effective for use as acleaning fluid applied to floors, most cleaning is done with a cleaningfluid that is a mixture of clean water and soap or detergent that reactswith contaminants to emulsify the contaminants into the water. Inaddition, it is known to clean floor surfaces with water and detergentmixed with other agents such as a solvent, a fragrance, a disinfectant,a drying agent, abrasive particulates and the like to increase theeffectiveness of the cleaning process.

The sponge or mop may also be used as a scrubbing element for scrubbingthe floor surface, and especially in areas where contaminants areparticularly difficult to remove from the floor. The scrubbing actionserves to agitate the cleaning fluid for mixing with contaminants aswell as to apply a friction force for loosening contaminants from thefloor surface. Agitation enhances the dissolving and emulsifying actionof the cleaning fluid and the friction force helps to break bondsbetween the surface and contaminants.

One problem with the manual floor cleaning methods of the prior art isthat after cleaning an area of the floor surface, the waste liquid mustbe rinsed from the mop or sponge, and this usually done by dipping themop or sponge back into the container filled with cleaning fluid. Therinsing step contaminates the cleaning fluid with waste liquid and thecleaning fluid becomes more contaminated each time the mop or sponge isrinsed. As a result, the effectiveness of the cleaning fluiddeteriorates as more of the floor surface area is cleaned.

While the traditional manual method is effective for floor cleaning, itis labor intensive and time consuming. Moreover, its cleaningeffectiveness decreases as the cleaning fluid becomes contaminated. Aneed exists in the art for an improved method for wet cleaning a floorsurface to provide an affordable wet floor cleaning device forautomating wet floor cleaning in the home.

In many large buildings, such as hospitals, large retail stores,cafeterias, and the like, there is a need to wet clean the floors on adaily or nightly basis, and this problem has been addressed by thedevelopment of industrial floor cleaning “robots” capable of wetcleaning floors. An example of one industrial wet floor cleaning deviceis disclosed in U.S. Pat. No. 5,279,672 by Betker et al., and assignedto Windsor Industries Inc. The disclosure of the '672 patent is hereinincorporated by reference it its entirety. Betker et al. disclose anautonomous floor cleaning device having a drive assembly providing amotive force to autonomously move the wet cleaning device along acleaning path.

The use of the word “robot” or “autonomous” to describe the Betker etal. device does not necessarily mean “unattended” or fullyautonomous—such devices are operator attended for many reasons. Onereason such devices are operator attended is because they weighthundreds of pounds and can cause significant damage in the event of asensor failure or unanticipated control variable. A more significantreason is because devices as proposed by Betker et al. are notphysically configured to escape or navigate among confined areas orobstacles, nor are they capable of being programmed to escape ornavigate among confined areas or obstacles. For example, the scrubberdisclosed in Betker et al. would often encounter the situation where ithas insufficient lateral space to turn in accordance with the necessarycontrolled radius and navigate around an obstacle, and in such a case“alerts the operator that the situation requires assistance,” asexpressly disclosed by Betker et al. The Betker et al. device is in someways semi-autonomous, but despite its rich sensor complement, it doesnot address fundamental principles of autonomous operation, includingphysical configuration and flexible response to its environment. TheBetker et al. device would likely clean for no more than a few minutesbefore getting stuck and requiring operator intervention.

The Betker et al. device provides a cleaning fluid dispenser fordispensing cleaning fluid onto the floor; rotating scrub brushes incontact with the floor surface for scrubbing the floor with the cleaningfluid, and a waste liquid recovery system, comprising a squeegee and avacuum system for recovering the waste liquid from the floor surface.While the device disclosed by Betker et al. is usable to autonomouslywet clean large floor areas, it is not suitable for the home market, andfurther, lacks many features, capabilities, and functionality of thepresent invention as described further herein. In particular, theindustrial autonomous cleaning device disclosed by Betker et al. is toolarge, costly and complex for use in the home and consumes too muchelectrical power to provide a practical solution for the home wet floorcleaning market. A fundamental shortcoming of Betker is that it appearsto be neither physically capable nor flexibly programmed to respond to acomplex environment, and is therefore designed to be frequently“rescued” by its attendant operator. Another is that its cleaningtechniques may not be effective in a robot that could be carried ormanually moved by a person, e.g., less than 20 kg.

Recently, improvements in conventional manual wet floor cleaning in thehome are disclosed in U.S. Pat. No. 5,968,281 by Wright et al., andassigned to Royal Appliance Mfg., entitled Method for Mopping and Dryinga Floor. The disclosure of the '281 patent is herein incorporated byreference it its entirety. Disclosed therein is a low cost wet moppingsystem for manual use in the home market. The wet mopping systemdisclosed by Wright et al. comprises a manual floor cleaning devicehaving a handle with a cleaning fluid supply container supported on thehandle. The device includes a cleaning fluid dispensing nozzle supportedon the handle for spraying cleaning fluid onto the floor and a floorscrubber sponge attached to the end of the handle for contact with thefloor. The device also includes a mechanical device for wringing wasteliquid out of the scrubbing sponge. A squeegee and an associated suctiondevice are supported on the end of the handle and used to collect wasteliquid up from the floor surface and deposit the waste liquid into awaste liquid container, supported on the handle separate from thecleaning solution reservoir. The device also includes a battery powersource for powering the suction device. While Wright et al. describes aself contained wet cleaning device as well as an improved wet cleaningmethod that separates waste liquid from cleaning fluid, the device ismanually operated and appears to lack robotic functionality (motordrive, autonomous control, etc.) and other benefits and featuresidentified in the present disclosure.

BRIEF SUMMARY OF THE INVENTION

The present invention overcomes the problems cited in the prior byproviding, inter alia, low cost autonomous robot capable of wet cleaningfloors and affordable for home use. The problems of the prior art areaddressed by the present invention which provides an autonomous cleaningrobot comprising a chassis and a transport drive system configured toautonomously transport cleaning elements over a cleaning surface. Therobot is supported on the cleaning surface by wheels in rolling contactwith the cleaning surface and the robot includes controls and driveelements configured to control the robot to generally traverse thecleaning surface in a forward direction defined by a fore-aft axis. Therobot is further defined by a transverse axis perpendicular to thefore-aft axis.

In particular, the surface cleaning robot includes two separate cleaningzones with a first cleaning zone configured to collect looseparticulates from the surface and with a second cleaning zone configuredto apply a cleaning fluid onto the surface, scrub the surface andthereafter collect a waste liquid from the surface. The surface cleaningrobot may also include at least two containers or compartments, carriedthereby, to store cleaning fluid and waste materials. In certainembodiments, one compartment is positioned at least partially directlyabove (with respect to gravity) the other, so that movements of fluidfrom one compartment to another do not significantly shift the center ofgravity of the robot.

The robot chassis carries a first cleaning zone A comprising cleaningelements arranged to collect loose particulates from the cleaningsurface across a cleaning width. The cleaning elements of the firstcleaning zone utilize a jet port disposed on a transverse edge of therobot and configured to blow a jet of air across a cleaning width of therobot towards the opposite transverse edge. A vacuum intake port isdisposed on the robot opposed to the jet port to suction up looseparticulates blown across the cleaning width by the jet port. Thecleaning elements of the first cleaning zone may suction up looseparticulates, utilize brushes to sweep the loose particulates intoreceptacle or otherwise remove the loose particulates from the surface.

The robot chassis may also carries a second cleaning zone B comprisingcleaning elements arraigned to apply a cleaning fluid onto the surface.The second cleaning zone also includes cleaning elements configured tocollect the cleaning fluid up from the surface after it has been used toclean the surface and may further include elements for scrubbing thecleaning surface and for smearing the cleaning fluid more uniformly overthe cleaning surface.

The robot includes a motive drive subsystem controlled by a mastercontrol module and powered by a self-contained power module forperforming autonomous movement over the cleaning surface. In one aspect,the invention relates to an autonomous cleaning robot having a chassissupported for transport over a cleaning surface, the chassis beingdefined by a fore-aft axis and a perpendicular transverse axis; a firstcollecting apparatus attached to the chassis and configured to collectloose particulates from the cleaning surface across a cleaning width,the cleaning width being disposed generally parallel with the transverseaxis; a liquid applicator, attached to the chassis and configured toapply a cleaning fluid onto the cleaning surface; and, wherein thearrangement of the first collecting apparatus with respect to the liquidapplicator causes the first collecting apparatus to precede the liquidapplicator over the cleaning surface when transporting the chassis in aforward direction.

In one embodiment of the above aspect, the autonomous cleaning robotalso includes a smearing element attached to the chassis and configuredto smear the cleaning fluid applied onto the cleaning surface to moreuniformly spread the cleaning fluid over the cleaning surface; whereinthe arrangement of the liquid applicator with respect to the smearingelement (or spreader brush) causes the liquid applicator to precede thesmearing element over the cleaning surface when transporting the chassisin a forward direction. In another embodiment, the robot includes ascrubbing element configured to scrub the cleaning surface; wherein thearrangement of the liquid applicator with respect to the scrubbingelement causes the liquid applicator to precede the scrubbing elementover the cleaning surface when transporting the chassis in the forwarddirection. In certain embodiments, the robot also includes a secondcollecting apparatus configured to collect waste liquid from thecleaning surface, the waste liquid comprising the cleaning fluid appliedby the liquid applicator plus any contaminants, removed from thecleaning surface by the clean fluid; wherein the arrangement of thescrubbing element with respect to the second collecting apparatus causesthe scrubbing element to precede the second collecting apparatus overthe cleaning surface as the chassis is transported in the forwarddirection.

In certain embodiments of the above aspect, the robot includes a firstwaste storage container, compartment, or tank attached to the chassisand arranged to receive the loose particulates therein, and/or a secondwaste storage container attached to the chassis and arranged to receivethe waste liquid therein. Some embodiments of the autonomous robot ofthe above aspect include a cleaning fluid storage container attached tothe chassis and configured to store a supply of the cleaning fluidtherein and to deliver the cleaning fluid to the liquid applicator. Insome embodiments, the cleaning fluid comprises water and/or water mixedwith any one of soap, solvent, fragrance, disinfectant, emulsifier,drying agent and abrasive particulates. In some embodiments, the firstand second waste containers are configured to be removable from thechassis by a user and to be emptied by the user, and/or said cleaningfluid storage container is configured to be removable from the chassisby a user and to be filled by the user. Certain embodiments include acombined waste storage container, compartment, or tank attached to thechassis and configured to receive the loose particulates from the firstcollecting apparatus and to receive the waste liquid from the secondcollecting apparatus therein. In other embodiments the waste storagecontainer is configured to be removable from the chassis by a user andto be emptied by the user. Still other embodiments include a cleaningfluid storage container, attached to the chassis and configured to storea supply of the cleaning fluid therein and to deliver the cleaning fluidto the liquid applicator, and in some cases, said cleaning fluid storagecontainer is configured to be user removable from the chassis and to befilled by the user.

In some embodiments of the above aspect, the autonomous cleaning robotfurther includes an integrated liquid storage container, attached to thechassis, and formed with two separate container portions, compartments,bladder(s), or tanks comprising; a waste storage container portionconfigured to receive the loose particulates from the first collectingapparatus and the waste liquid from the second collecting apparatustherein; and, a cleaning fluid storage container, compartment, bladder,or tank portion configured to store a supply of the cleaning fluidtherein and to deliver the cleaning fluid to the liquid applicator. Inother embodiments, the autonomous cleaning robot of the above aspectincludes the integrated liquid storage container configured to beremovable from the chassis by a user and for the cleaning fluid storagecontainer to be filled by and for the waste storage container to beemptied by the user. In some embodiments of the above aspect, the robotincludes a second collecting apparatus configured to collect wasteliquid from the cleaning surface, the waste liquid comprising thecleaning fluid applied by the liquid applicator plus any contaminants,removed from the cleaning surface by the cleaning fluid; and, whereinthe arrangement of the liquid applicator with respect to the secondcollecting apparatus causes the liquid applicator to precede the secondcollecting apparatus over the cleaning surface as the chassis istransported in the forward direction. Certain embodiments of the aboveaspect include a smearing element or spreader brush attached to thechassis and configured to smear the cleaning fluid applied onto thecleaning surface to more uniformly spread the cleaning fluid over thecleaning surface; and, wherein the arrangement of the liquid applicatorwith respect to the smearing element causes the liquid applicator toprecede the smearing element or spreader brush over the cleaning surfacewhen transporting the chassis in a forward direction.

In some embodiments, the robot includes a waste storage container,compartment, or tank attached to the chassis and configured to receivethe loose particulates from the first collecting apparatus and toreceive the waste liquid from the second collecting apparatus therein,and in certain cases, the waste storage container is configured to beremovable from the chassis by a user and to be emptied by the user. Someembodiments of the robot include a cleaning fluid storage container,attached to the chassis and configured to store a supply of the cleaningfluid therein and to deliver the cleaning fluid to the liquidapplicator, and in some cases, said cleaning fluid storage container isconfigured to be removable from the chassis by a user and to be filledby the user. In other embodiments, the robot of the above aspectincludes an integrated liquid storage container or tank, attached to thechassis, and formed with two separate container portions comprising; awaste storage container portion configured to receive the looseparticulates from the first collecting apparatus and to receive thewaste liquid from the second collecting apparatus therein; and, acleaning fluid storage container, compartment, bladder, or tankconfigured to store a supply of the cleaning fluid therein and todeliver the cleaning fluid to the liquid applicator. In certainembodiments, said integrated liquid storage container or tank isconfigured to be removable from the chassis by a user and for thecleaning fluid storage container to be filled by and for the wastestorage container or tank to be emptied by the user.

Some embodiments of the above aspect include a motive drive subsystemattached to chassis for transporting the chassis over the cleaningsurface; a power module attached to the chassis for deliveringelectrical power to each of a plurality of power consuming subsystemsattached to the chassis; and, a master control module attached to thechassis for controlling the motive drive module, the first collectingapparatus, and the liquid applicator, to autonomously transport therobot over the cleaning surface and to autonomously clean the cleaningsurface. Some embodiments may also include a sensor module configured tosense conditions external to the robot and to sense conditions internalto the robot and to generate electrical sensor signals in response tosensing said conditions; a signal line for communicating the electricalsensor signals to the master control module; and, a controllerincorporated within the master control module for implementingpredefined operating modes of the robot in response to said conditions.

Some embodiments include a user control module configured to receive aninput command from a user and to generate an electrical input signal inresponse to the input command; a signal line for communicating theelectrical input signal to the master control module; and, a controllerincorporated within the master control module for implementingpredefined operating modes of the robot in response to the inputcommand. In certain embodiments, the autonomous cleaning robot includesan interface module attached to the chassis and configured to provide aninterface between an element external to the robot and at least oneelement attached to the chassis. In some embodiments, the elementexternal to the robot comprises one of a battery-charging device and adata processor. Some embodiments include an interface module attached tothe chassis and configured to provide an interface between an elementexternal to the robot and at least one element attached to the chassis.In some embodiments, the element external to the robot comprises one ofa battery-charging device, a data processor, a device for autonomouslyfilling the cleaning fluid storage container with cleaning fluid, and adevice for autonomously emptying the waste liquid container.

Certain embodiments of robots of the above aspect include an air jetport, attached to the chassis disposed at a first edge of the cleaningwidth and configured to blow a jet of air across the cleaning widthproximate to the cleaning surface, to thereby force loose particulateson the cleaning surface to move away from the first edge in a directiongenerally parallel with the transverse axis; an air intake port,attached to the chassis and disposed at a second edge of the cleaningwidth, opposed from the first edge and proximate to the cleaning surfacefor suctioning up the loose particulates; a waste storage containerconfigured to receive the loose particulates from the air intake port;and a fan assembly configured to generate a negative pressure within thewaste storage container, compartment, or tank. In some embodiments, thefan assembly is further configured to generate a positive air pressureat the air jet port.

In other embodiments the second collecting apparatus includes a squeegeeattached to the chassis and formed with a longitudinal ridge disposedproximate to the cleaning surface and extending across the cleaningwidth for providing a liquid collection volume at a forward edge of theridge, said longitudinal ridge collecting waste liquid within the liquidcollection volume as the chassis is transported in the forwarddirection; a vacuum chamber partially formed by the squeegee disposedproximate to the longitudinal ridge and extending across the cleaningwidth; a plurality of suction ports passing through the squeegee forproviding a plurality of fluid passages for fluidly connecting theliquid collection volume and the vacuum chamber; and a vacuum forgenerating a negative air pressure within the vacuum chamber for drawingwaste liquid collected within the liquid collection volume into thevacuum chamber. Some additional embodiments also include a waste storagecontainer configured to receive the waste liquid from the vacuumchamber, at least one fluid conduit fluidly connecting the vacuumchamber and the waste storage container, compartment or tank; and a fanassembly configured to generate a negative air pressure within the wastestorage container and the vacuum chamber to thereby suction waste liquidup from the cleaning surface and deposit the waste liquid in the wastestorage container. Other embodiments of the second collecting apparatusincorporate a squeegee attached to the chassis and formed with alongitudinal ridge disposed proximate to the cleaning surface andextending across the cleaning width for providing a liquid collectionvolume at a forward edge of the ridge, said longitudinal ridgecollecting waste liquid within the liquid collection volume as thechassis is transported in the forward direction; a vacuum chamberpartially formed by the squeegee disposed proximate to the longitudinalridge and extending across the cleaning width; a plurality of suctionports passing through the squeegee for providing a plurality of fluidpassages for fluidly connecting the liquid collection volume and thevacuum chamber; and a vacuum for generating a negative air pressurewithin the vacuum chamber for drawing waste liquid collected within theliquid collection volume into the vacuum chamber.

Still other embodiments of the above aspect include a waste storage tank(or compartment) configured to receive the waste liquid from the vacuumchamber, at least one fluid conduit fluidly connecting the vacuumchamber and the waste storage container or tank; and, a fan assemblyconfigured to generate a negative air pressure within the waste storagecontainer and the vacuum chamber to thereby suction waste liquid fromthe cleaning surface and deposit the waste liquid in the waste storagecontainer or tank. In some embodiments, the fan assembly is configuredto generate a positive air pressure at the air jet port.

In another aspect, the invention relates to an autonomous cleaning robotfor transporting cleaning elements over a cleaning surface including achassis, supported in rolling contact with the cleaning surface fortransporting the chassis in a forward direction defined by a fore-aftaxis, the chassis being further defined by a transverse axis; a firstcleaning zone comprising cleaning elements attached to the chassis andarranged to collect loose particulates from the cleaning surface acrossa cleaning width, the cleaning width being disposed generallyperpendicular with the fore-aft axis; a second cleaning zone comprisingcleaning elements attached to the chassis and arranged to apply acleaning fluid onto the cleaning surface and to collect a waste liquidfrom the cleaning surface across the cleaning width, said waste liquidcomprising the cleaning fluid plus any contaminants removed from thecleaning surface by the cleaning fluid; and a motive drive subsystemcontrolled by a master control module and powered by a power module, themotive drive subsystem, master control module and power module eachbeing electrically interconnected and attached to the chassis configuredto autonomously transporting the robot over the cleaning surface and toclean the cleaning surface. In some embodiments of this aspect, therobot is configured with a circular cross-section having a verticalcenter axis and wherein said fore-aft axis, said transverse axis andsaid vertical axis are mutually perpendicular and wherein the motivedrive subsystem is configured to rotate the robot about the centervertical axis for changing the orientation of the forward traveldirection.

In another aspect, the invention relates to a surface cleaning apparatushaving a chassis defined by a fore-aft axis and a perpendiculartransverse axis, the chassis being supported for transport over thesurface along the fore-aft axis, the chassis including a firstcollecting apparatus attached thereto and configured to collect looseparticulates from the surface over a cleaning width disposed generallyparallel with the transverse axis, the first collecting apparatusincluding an air jet port configured to expel a jet of air across thecleaning width; an air intake port configured to draw air and looseparticulates in; wherein the air jet port and the air intake port aredisposed at opposing ends of the cleaning width with the air jet portexpelling the jet of air generally parallel with the surface andgenerally directed toward the air intake port. In an embodiment of theabove aspect, the first collecting apparatus further includes a channelformed with generally opposed forward and aft edges, extending generallyparallel with the transverse axis across the cleaning width, andgenerally opposed left and right edges, extending generally orthogonalto said forward and aft edges; wherein the air jet port is disposed atone of said left and right edges and the air intake port is disposed atthe other of said left and right edges. In other embodiments, thesurface cleaning apparatus further includes a first compliant doctor orair flow guide blade disposed across the cleaning width and fixedlyattached to a bottom surface of the chassis proximate to said aft edgeand extending from said bottom surface to the surface for guiding thejet of air and loose particulates across the cleaning width.

In other embodiments of the above aspect, the surface cleaning apparatusfurther includes a second compliant doctor or air flow guide bladefixedly attached to said bottom surface and extending from said bottomsurface to the surface, for guiding the jet of air and looseparticulates into the air intake port. In still other embodiments, theapparatus includes a rotary fan motor having a fixed housing and arotating shaft extending therefrom; a fan impeller configured to moveair when rotated about a rotation axis, said fan impeller being fixedlyattached to the rotating shaft for rotation about the rotation axis bythe fan motor; a housing for housing the fan impeller in a hollow cavityformed therein and for fixedly supporting the motor fixed housingthereon, the housing being further configured with an air intake portthrough which air is drawn in to the cavity, and an air exit portthrough which air is expelled out of the cavity when the impeller isrotated; and a first fluid conduit fluidly connected between the fan airintake port and the air intake port of said first collecting apparatus;therein each of the elements is attached to the chassis. In someembodiments, the apparatus includes a waste storage container attachedto the chassis and fluidly interposed within said first fluid conduitbetween the fan air intake port and the air intake port. In someembodiments, the waste storage container is configured to be removablefrom the chassis by a user and to be emptied by the user.

Still other embodiments include an air filter element interposed withinsaid first fluid conduit between the waste storage container and the fanair intake port for filtering loose contaminates from air being drawn inthrough the fan air intake port, and may also include a second fluidconduit fluidly connected between the fan exit port and the air jet portof said first collecting apparatus. In other embodiments, the surfacecleaning apparatus further includes a second collecting apparatusattached to the chassis and disposed aft of the first collectingapparatus for collecting liquid from the surface over the cleaningwidth. In some embodiments, the second collecting zone includes asqueegee fixedly attached to the chassis aft of the first collectingapparatus and extending from a bottom surface of the chassis to thesurface across the cleaning width for collecting liquid in a liquidcollection volume formed between the squeegee and the surface, thesqueegee further forming a vacuum chamber and providing a plurality ofsuction ports disposed across the cleaning width and fluidly connectingthe vacuum chamber and the liquid collection volume; and a vacuum forgenerating a negative air pressure inside the vacuum chamber to therebydraw liquid into the vacuum chamber through the plurality of suctionports fluidly connected with the collection volume.

Other embodiments of the surface cleaning apparatus of the above aspectinclude a rotary fan motor having a fixed housing and a rotating shaftextending therefrom; a fan impeller configured to move air when rotatedabout a rotation axis, said fan impeller being fixedly attached to therotating shaft for rotation about the rotation axis by the fan motor; ahousing for housing the fan impeller in a hollow cavity formed thereinand for fixedly supporting the motor fixed housing thereon, the housingbeing further configured with an air intake port through which air isdrawn in to the cavity, and an air exit port through which air isexpelled out of the cavity when the impeller is rotated; a first fluidconduit fluidly connected between the fan air intake port and the airintake port of said first collecting apparatus; and a third fluidconduit fluidly connected between the fan air intake port and the vacuumchamber; wherein these elements are attached to the chassis. The surfacecleaning apparatus may also include a second fluid conduit fluidlyconnected between the fan exit port and the air jet port of said firstcollecting apparatus, and/or a waste storage container or tank attachedto the chassis and configured to store the liquid collected from thesurface. Still other embodiments utilize a waste storage containerattached to the chassis and configured to store the liquid collectedfrom the surface, said waste storage container or tank being fluidlyinterposed within said third fluid conduit. In some embodiments, thecleaning apparatus includes a waste storage container attached to thechassis and configured to store the liquid collected from the surface,said waste storage container being fluidly interposed within said firstand said third fluid conduits. In certain cases, said waste storagecontainer or tank includes a sealed waste container for storing looseparticulates collected by the first collecting apparatus and for storingliquid collected by the second collecting apparatus and having at leastone access port formed therein for emptying waste from the container;and a plenum incorporated into a top wall of the sealed container suchthat the plenum is disposed vertically above the sealed waste containerduring operation of the cleaning apparatus; and wherein the plenum isconfigured with ports for fluidly interposing within each of said first,said second and said third fluid conduits.

In some embodiments, the waste storage container is configured to beremovable from the chassis by a user and to be emptied by the user.Certain other embodiments include a cleaning fluid applicator assembly,attached to the chassis between the first collecting apparatus and thesecond collecting apparatus for applying a cleaning fluid onto thesurface across the cleaning width; and a sealed cleaning fluid storagecontainer or tank for holding a supply of the cleaning fluid therein thestorage container including at least one access port formed therein forfilling the container with the cleaning fluid. In other embodiments,said sealed waste container and said sealed cleaning fluid container areintegrated into a liquid storage container module and wherein theintegrated liquid storage container module is configured to be removablefrom the chassis by a user for filling with cleaning fluid and foremptying waste therefrom. In some embodiments, the surface cleaningapparatus further includes a smearing element attached the chassis aftof the liquid applicator assembly and configured to smear the cleaningfluid across the cleaning width; and a scrubbing element, scrub brush,wiper, or wipe cloth attached to the chassis aft of the smearing elementor spreader brush for scrubbing the surface across the cleaning width.In some embodiments, the surface cleaning apparatus further comprises amotive drive subsystem controlled by a master control module and powerby a power module, each attached to the chassis, for autonomouslytransporting the surface cleaning apparatus over the surface. A pad,cloth, or other absorbent wiper extending essentially across thecleaning width may be placed before or after the cleaning head toprepare the surface or absorb wetness behind the cleaning head asappropriate. The entire cleaning head is formed from materials thatwithstand water and temperature extremes sufficient for the cleaninghead to be “dishwasher safe.”

In other embodiments, the surface cleaning apparatus further includes asensor module configured to sense conditions and to generate electricalsensor signals in response to sensing said conditions; a signal line forcommunicating the electrical sensor signals to the master controlmodule; and a controller incorporated within the master control modulefor implementing predefined operating modes in response to sensing saidconditions. Still other embodiments include a motive drive subsystemcontrolled by a master control module and power by a power module, eachattached to the chassis, for autonomously transporting the surfacecleaning apparatus over the surface. Other embodiments of the surfacecleaning apparatus further include a sensor module configured to senseconditions and to generate electrical sensor signals in response tosensing said conditions; a signal line for communicating the electricalsensor signals to the master control module; and a controllerincorporated within the master control module for implementingpredefined operating modes in response to sensing said conditions.

In yet another aspect, the invention relates to a surface cleaningapparatus having an autonomous transport drive subsystem controlled by amaster control module, a sensor module for sensing conditions, a powermodule and cleaning elements all supported on a chassis and powered bythe power module for moving the chassis over the surface in accordancewith predefined operating modes and in response to conditions sensed bythe sensor module, the elements being configured with a cleaning widthdisposed generally orthogonal to a forward transport direction andwherein the cleaning elements comprise; a first collecting apparatus forcollecting loose particulates from the surface across the cleaningwidth, said first collecting apparatus A being positioned on the chassisto advance over the surface first as the chassis is transported in aforward transport direction; a cleaning fluid applicator for applyingcleaning fluid onto the surface across the cleaning width, said cleaningfluid applicator being positioned on the chassis to advance over thesurface second as the chassis is transported in a forward transportdirection; a smearing element for smearing the cleaning fluid appliedonto the surface across the cleaning width, said smearing element orspreader brush being positioned on the chassis to advance over thesurface third as the chassis is transported in a forward transportdirection; an active scrubbing element for actively scrubbing thesurface across the cleaning width, said active scrubbing element beingpositioned on the chassis to advance over the surface fourth as thechassis is transported in a forward transport direction; a secondcollecting apparatus for collecting waste liquid from the surface, saidsecond collecting apparatus being positioned on the chassis to advanceover the surface fifth as the chassis is transported in a forwardtransport direction; and, an integrated storage container or tank modulecomprising a waste storage container for storing loose particulatescollected by said first collecting apparatus and waste liquid collectedby said second collecting apparatus, a cleaning fluid supply containerfor storing a supply of the cleaning fluid, and wherein the integratedstorage container or tank module is configured to be removed from thechassis by a user, filled with cleaning fluid and emptied of waste andthen reinstalled onto the chassis by the user.

In yet an additional aspect, the invention relates to a surface cleaningapparatus having a chassis defined by a fore-aft axis and aperpendicular transverse axis for supporting cleaning elements thereonand for transporting the cleaning elements over the surface along thefore-aft axis and wherein the cleaning elements are disposed to cleanacross a cleaning width disposed generally orthogonal to the fore-aftaxis with a left end and a right end defining opposing edges of thecleaning width; and a liquid applicator comprising at least one nozzledisposed at one of said left end and said right end for ejectingcleaning fluid therefrom, said cleaning fluid being ejected withsufficient volume and pressure to distribute cleaning fluid across thecleaning width. In certain embodiments of the above aspect, the cleaningfluid comprises water and/or any one of soap, solvent, fragrance,disinfectant, emulsifier, drying agent and abrasive particulates.

In some embodiments of the above aspect, the apparatus includes asmearing element attached to the chassis aft of the position of the atleast one nozzle and extending from the chassis to the surface acrossthe cleaning width for smearing the cleaning fluid, and may include ascrubbing element attached to the chassis aft of the position of the atleast one nozzle and extending from the chassis to the surface acrossthe cleaning width for scrubbing the surface. In some embodiments, thescrubbing element is attached to the chassis aft of the position of theat least one nozzle and extending from the chassis to the surface acrossthe cleaning width for scrubbing the surface. The cleaning apparatus mayalso include a collecting apparatus attached to the chassis aft of theposition of the at least one nozzle and extending from the chassis tothe surface across the cleaning width for collecting waste liquid fromthe surface. In some embodiments, the liquid applicator a first nozzledisposed at the left end for ejecting cleaning fluid therefrom, saidcleaning fluid being ejected from the first nozzle with sufficientvolume and pressure to distribute cleaning fluid across the cleaningwidth, a second nozzle disposed at the right end for ejecting cleaningfluid therefrom, said cleaning fluid being ejected from the secondnozzle with sufficient volume and pressure to distribute cleaning fluidacross the cleaning width; and wherein the first nozzle and the secondnozzle are co-located on the fore-aft axis.

In certain embodiments of the above aspect each of the first and secondnozzles ejects a discrete burst cleaning fluid in accordance with aburst frequency and wherein the burst frequency of the first nozzle issubstantially opposite in phase with respect to the burst frequency ofthe second nozzle. In some embodiments, the surface cleaning apparatusalso includes an autonomous transport drive subsystem, a sensor modulefor sensing conditions and a power module all supported by the chassisand controlled by a master control module to autonomously move thecleaning elements substantially over the entire surface over the surfacein accordance with predefined operating modes and in response toconditions sensed by the sensor module. Still other embodiments utilizean autonomous transport drive subsystem, a sensor module for sensingconditions and a power module all supported by the chassis andcontrolled by a master control module to autonomously move the cleaningelements substantially over the entire surface over the surface inaccordance with predefined operating modes and in response to conditionssensed by the sensor module.

Other embodiments of the above aspect include an autonomous transportdrive subsystem, a sensor module for sensing conditions and a powermodule all supported by the chassis and controlled by a master controlmodule to autonomously move the cleaning elements substantially over theentire surface over the surface in accordance with predefined operatingmodes and in response to conditions sensed by the sensor module. In someembodiments, the master control module is configured to vary the burstfrequency in accordance with a desired rate for applying cleaning fluidonto surface, and in some cases, the master control module is configuredto vary the burst frequency to apply cleaning fluid onto the surface ata substantially uniform volume of approximately 2 ml per square foot.

In some embodiments, the surface cleaning apparatus also includes aliquid storage container, carried on the chassis, for storing a supplyof the cleaning fluid therein; a diaphragm pump assembly configured witha first a first pump portion for drawing cleaning fluid from thecontainer and for delivering the cleaning fluid to the at least onenozzle; and a mechanical actuator for mechanically actuating the firstpump portion. Still other embodiments include an autonomous transportdrive subsystem, a sensor module for sensing conditions and a powermodule all supported by the chassis and controlled by a master controlmodule to autonomously move the cleaning elements substantially over theentire surface over the surface in accordance with predefined operatingmodes and in response to conditions sensed by the sensor module; aliquid storage container, carried on the chassis, for storing a supplyof the cleaning fluid therein; a diaphragm pump assembly having a firsta first pump portion for drawing cleaning fluid from the container andfor delivering the cleaning fluid to the first nozzle and a second pumpportion for drawing cleaning fluid from the container and for deliveringthe cleaning fluid to the second nozzle; and a mechanical actuator formechanically actuating the first pump portion and the second pumpportion.

In certain embodiments of the above aspect, the diaphragm pump assemblyincludes a flexible element mounted between a non-flexible upper chamberelement and a non-flexible lower chamber element, said flexible elementbeing formed with a first pump chamber and a first actuator nippleattached thereto and a second pump chamber and a second actuator nippleattached thereto; an actuator link pivotally attached to the pumpassembly for pivoting between a first actuator position and a secondactuator position, the actuator link being fixedly attached to each ofsaid first and said second actuator nipples and wherein movement of theactuator link toward the first actuator position decreases the volumethe first pump chamber and increases the volume of the second pumpchamber and further wherein movement of the actuator link toward thesecond actuator position increases the volume the first pump chamber anddecreases the volume of the second pump chamber; a cam elementconfigured with a circumferential cam profile and supported to move theactuator link between the first actuator position and the secondactuator position; and a cam rotary drive, controlled by the mastercontroller, for rotating the cam element in accordance with a cam rotarydrive pattern.

In another aspect, the invention relates to a method for cleaning asurface with a cleaning apparatus, the method including the steps oftransporting a chassis over the surface in a forward transport directiondefined by a defined by a fore-aft axis, said chassis including cleaningelements supported thereon, and wherein the cleaning elements have acleaning width disposed generally orthogonal to the fore-aft axis andwherein the cleaning width has a left end and an opposing right end; andejecting a volume of cleaning fluid from a first nozzle attached to thechassis at one of said left end and said right end, said first nozzlebeing configured to eject cleaning fluid therefrom, said cleaning fluidbeing ejected with sufficient volume and pressure to distribute cleaningfluid across the cleaning width. In certain embodiments, the method mayalso include ejecting a volume of cleaning fluid from a second nozzleattached to the chassis at the other of said left end and said right endand co-located on the fore-aft axis with respect to the first nozzle,said second nozzle being configured to eject cleaning fluid therefrom,said cleaning fluid being ejected with sufficient volume and pressure todistribute cleaning fluid across the cleaning width; and ejectingcleaning fluid from each of the first nozzle and the second nozzle indiscrete bursts of cleaning fluid in accordance with a burst frequencyand wherein the burst frequency of the first nozzle is substantiallyopposite in phase with respect to the burst frequency of the secondnozzle.

In still other embodiments, the method includes smearing the cleaningfluid across the cleaning width using a smearing element or spreaderbrush attached to the chassis aft of the colocated position of the firstnozzle and the second nozzle, said smearing element extending across thecleaning width. Other embodiments may include scrubbing the surfaceacross the cleaning width using a scrubbing element, scrub brush, wiper,or wipe cloth attached to the chassis aft of the co-located position ofthe first nozzle and the second nozzle, said scrubbing element extendingacross the cleaning width. Still other embodiments include collectingwaste liquid from the surface across the cleaning width using acollecting apparatus attached to the chassis aft of the co-locatedposition of the first nozzle and the second nozzle, said collectingapparatus extending across the cleaning width. In some embodiments ofthe method of the above aspect, the chassis further includes anautonomous transport drive subsystem, a sensor module for sensingconditions and a power module all supported thereon and controlled by amaster control module and wherein transporting the chassis over thesurface further includes controlling the transport drive subsystem inaccordance with predefined operating modes and in response to conditionssensed by the sensor module to transport the cleaning elementssubstantially over the entire surface.

According to one aspect of the present invention, a surface treatmentrobot includes a robot body having an outer perimeter formedsubstantially as a shape of constant width, driven forward by at leastone circulating member, and a dispensed material compartment that holdsmaterial to be dispensed by the robot. A wet cleaning head that employsone or more wet cleaning member(s) to clean along a cleaning width lineof the robot with the assistance of dispensed material, the wet cleaninghead defining a cleaning width. A waste material compartment holdsmaterial picked up by the robot. Each of the dispensed materialcompartment and waste material compartment being shaped and positionedto place the center of gravity of the dispensed material compartmentvolume less than ½ of the cleaning width from the center of gravity ofthe waste material compartment volume.

For example, one embodiment of the robot has a cleaning width of about30 cm, and each of these centers of gravity is less than 15 cm from theother. The center of gravity of the volume is readily understood as thecenter of the empty volume; however, it may also be understood as thecenter of gravity of a body of fluid filling the volume (most fluidsdiscussed herein would approximate the specific gravity of water).Surface treatment includes cleaning and other treatments as discussedherein. The shapes of constant width are also defined herein, notingthat not all such shapes are regular, and that one embodiment of therobot is substantially cylindrical. The wet cleaning member includesbrushes, sponges, wipers, and the like. A circulating member wouldinclude a rotating wheel, a rotating brush, and/or one or morecirculating belts or webs. The material need not be wet, although mostwould be.

Optionally, each of the dispensed material compartment and wastematerial compartment is shaped and positioned to place the combinedcenter of gravity of the dispensed material compartment volume and thewaste material compartment volume less than ½ the cleaning width from acenter of the at least one circulating member. The center of a rotatingbrush would be the midpoint along the axis, the center of a rotatingbelt would be along the midpoint of the contact area with the surface.Further optionally, each of the dispensed material compartment and wastematerial compartment are shaped and positioned to place of the center ofgravity of the dispensed material compartment volume substantiallydirectly above or below the center of gravity of the waste materialcompartment volume. “Substantially directly” means, in one instance,above or below one another and vertical normals from each center ofgravity are within ¼ of the cleaning width from one another.

According to another aspect of the invention, a surface treatment robotincludes a robot body having an outer perimeter formed substantially asa shape of constant width, and at least two circulating drive membersthat drive the robot body forward and steer the robot body. A dispensedfluid compartment that holds fluid to be dispensed by the robot; and apowered scrubber drives at least one scrubbing element to clean, withthe assistance of dispensed fluid, substantially along a line of maximumwidth of the shape of constant width, the driven scrubbing elementextending to substantially within 1 cm of a tangential edge of the robotbody. By placing the scrubber along the line of maximum width of aconstant width shape such as a cylinder, the edge of the cleaning areacan be brought to the edge of the robot, permitting the robot to edgeclean within 1 cm of a wall. Placing the wheels along the line ofmaximum width would prevent this. Again, circulating includes rotatingmembers such as wheels or brushes, but also circulating belts or webs.

If the cleaning head is along the maximum width, the widest cleaninghead can be obtained by placing the least two circulating drive membersare placed along a line at which the width of the robot is less than themaximum width of the robot. Optionally, the robot also includes a wetvacuum that picks up the dispensed fluid after the scrubbing element hascleaned with the assistance of the dispensed fluid, and a waste fluidcompartment that holds fluid picked up by the wet vacuum unit. The wastefluid compartment and dispensed fluid compartment may be integralcompartments within a same fluid tank module that is readily removableas a module from the robot body.

According to another aspect of the invention, a surface treatment robotincludes robot body having an outer perimeter formed substantially as ashape of constant width, driven forward by at least one rotating member,and a dispensed fluid compartment that holds fluid to be dispensed bythe robot. A powered wet cleaning head employs at least one powered wetcleaning member to clean a cleaning width along a cleaning width line ofthe robot with the assistance of dispensed fluid. A waste materialcompartment holds waste fluid picked up by the robot. The wet cleaninghead has a cleaning width with respect to total robot mass of the robotbody, dispensed material compartment when empty, wet cleaning head, andwaste material compartment when full of waste fluid picked up by therobot, of more than or equal to three centimeters of cleaning width perkilogram of total robot mass.

An example robot according to the invention has a cleaning width ofabout 30 cm, and a mass of about 3-5 kg. Such a robot has about 10 cm toabout 6 cm of powered cleaning width per kilogram of fully loaded robot,a less efficient version, but still acceptable, could be 3 cm of poweredcleaning width per kilogram of robot mass. This cleaning width permitssufficient work to be done per unit time, and the amount of weight issufficient to provide enough traction for the cleaning width. Moreover,the robot does not become excessively large or inefficient by limitingthe amount of weight. This combination provides the best balance ofcleaning time versus maneuverability versus manageability.

Optionally, the powered wet cleaning head includes a powered circulatingscrubber that scrubs the surface to be cleaned along a cleaning widthline of the robot with the assistance of dispensed fluid. Further, thepowered wet cleaning head may include a powered wet vacuum that picks upthe waste fluid. Each of these contributes to the cleaning width, andmay contribute either to drag or to motive force. The weight placed onthe cleaning width may be limited to reduce or otherwise limit theamount of drag.

According to yet another aspect of the invention, a surface treatmentrobot includes a robot body having an outer perimeter formedsubstantially as a shape of constant width, driven forward by at leastone rotating member, and a wet cleaning head that employs at least onecirculating wet cleaning member to clean a cleaning width along acleaning width line of the robot with the assistance of dispensed fluid.A tank that accommodates a fluid compartment stores fluid, and the robotbody includes a mount that receives the tank. A fluid connection betweenthe tank and the robot body and a vacuum connection between the tank andthe robot body are provided. A coupling mechanically engages the tank tothe robot body, the engagement of the coupling simultaneously sealingboth the fluid connection and the vacuum connection.

With this construction, the robot may be prepared for use with onecoupling, which completes form of the robot, the mechanical integrity ofthe robot, the vacuum connection (and seal) and fluid connection (andseal).

Optionally, the tank forms at least one quarter of the outer profile ofthe robot, wherein engagement of the coupling engagement of completes asubstantially smooth outer profile of the robot. Alternatively, the tankforms at least one quarter of the outer peripheral surface of the robotincluding a part of the perimeter of the shape of constant width, andwherein engagement of the coupling engagement of substantially completesthe perimeter of the shape of constant width. In either case, the robotis permitted to autonomously turn to escape confined spaces and cornersby virtue of the outer profile, and space is efficiently maximized byavoiding the use of double and triple walls to house the tank within therobot body.

In one embodiment, a method for controlling a mobile robot may includespinning a brush in a first direction when the mobile robot movesforward; and deactivating the sweeping brush when the mobile robot movesin a reverse direction. In accordance with another embodiment, a methodfor controlling a mobile robot may include distributing fluid via a pumpwhen the mobile robot operates in a cleaning mode; and deactivating thepump when the mobile robot is not moving forward. In accordance with yetanother embodiment, a method for controlling a mobile robot may includetraversing a cleaning surface and distributing cleaning fluid on thecleaning surface during a cleaning cycle; and traversing the cleaningsurface without distributing the cleaning fluid on the cleaning surfaceduring a drying cycle. Also, the method may further includetransitioning from the cleaning cycle to the drying cycle when a powersupply voltage declines; or applying vacuum suction to the cleaningsurface when the mobile robot operates in the drying mode. In accordancewith another embodiment, a method for sensing fluid in a mobile robothaving at least first and second electrodes may include swappingpolarity between the first and second electrode; detecting a resistancebetween the first and second electrodes; and determining whether fluidis present based on the detected resistance between the first and secondelectrodes.

In another aspect, the invention relates to a liquid cleaner utilizedwith a robot cleaner, wherein the cleaner includes alkyl polyglucoside(for example, at 1-3% concentration) and tetrapotassiumethylenediamine-tetraacetate (tetrapotassium EDTA) (for example, at0.5-1.5% concentration).

In another aspect, the invention relates to a tire material including achloroprene homopolymer stabilized with thiuram disulfide black with adensity of 14-16 pounds per cubic foot, or approximately 15 pounds percubic foot foamed to a cell size of 0.1 mm plus or minus 0.02 mm. Incertain embodiments, the tire has a post-foamed hardness of about 69 to75 Shore 00. In other embodiments of the above aspects, the inventionrelates to tires, including, for example, those made of neoprene andchloroprene, and other closed cell rubber sponge materials. Tires madeof polyvinyl chloride (PVC) and acrylonitrile-butadiene (ABS) (with orwithout other extractables, hydrocarbons, carbon black, and ash) mayalso be used.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention will best be understood from adetailed description of the invention and a preferred embodiment thereofselected for the purposes of illustration and shown in the accompanyingdrawings in which:

FIG. 1 depicts an isometric view of a top surface of an autonomouscleaning robot according to the present invention.

FIG. 2 depicts an isometric view of a bottom surface of a chassis of anautonomous cleaning robot according to the present invention.

FIG. 3 depicts an exploded view of a robot chassis having robotsubsystems attached thereto according to the present invention.

FIG. 4 depicts a schematic block diagram showing the interrelationshipof subsystems of an autonomous cleaning robot according to the presentinvention.

FIG. 5 depicts a schematic representation of a liquid applicatorassembly according to the present invention.

FIG. 6 depicts a schematic section view taken through a stop valveassembly installed within a cleaning fluid supply tank according to thepresent invention.

FIG. 7 depicts a schematic section view taken through a pump assemblyaccording to the present invention.

FIG. 8 depicts a schematic top view of a flexible element used as adiaphragm pump according to the present invention.

FIG. 9 depicts a schematic top view of a nonflexible chamber elementused in the pump assembly according to the present invention.

FIG. 10 depicts a schematic exploded isometric view of a scrubbingmodule according to the present invention.

FIG. 11 depicts an isometric rotatable scrubbing brush according to thepresent invention.

FIG. 12A depicts a schematic section view taken through a secondcollecting apparatus used for collecting waste liquid according to thepresent invention.

FIG. 12B depicts a schematic section view of an alternative collectingapparatus used for collecting waste liquid according to the presentinvention.

FIG. 13 is a schematic block diagram showing elements of a drive moduleused to rotate the scrubbing brush according to the present invention.

FIG. 14 is a schematic representation of an air moving system accordingto the present invention.

FIG. 15 depicts a schematic exploded isometric view of a fan assemblyaccording to the present invention.

FIG. 16 depicts a schematic exploded isometric view showing elements ofan integrated liquid storage module according to the present invention.

FIG. 17 depicts an external view of the integrated liquid storage moduleremoved from the cleaning robot according to the present invention.

FIG. 18 depicts a schematic exploded view of a nose wheel moduleaccording to the present invention.

FIG. 19 depicts a schematic section view taken through a nose wheelassembly according to the present invention.

FIG. 20 depicts a schematic exploded view of a drive wheel assemblyaccording to the present invention.

FIG. 21 depicts an exploded view of a robot chassis having robotsubsystems attached thereto according to an embodiment of the presentinvention.

FIG. 22 depicts an exploded view of a robot chassis having robotsubsystems attached thereto according to an embodiment of the presentinvention.

FIG. 23 depicts an exploded isometric view of a cleaning head orscrubbing module in accordance with one embodiment of the presentinvention.

FIG. 24 depicts an isometric view of a fan assembly in accordance withone embodiment of the present invention.

FIG. 25 depicts an exploded isometric view of a fan assembly inaccordance with one embodiment of the present invention.

FIG. 26 depicts an exploded isometric view of a fan assembly inaccordance with one embodiment of the present invention.

FIG. 27 depicts an exploded view of a robot chassis having an integratedtank according to an embodiment of the present invention.

FIG. 28 depicts a plan view of a sealing flap and airfoil within theplenum of the integrated tank depicted in FIG. 27.

FIG. 29 depicts a side section view of the sealing flap and airfoilwithin the plenum of the integrated tank depicted in FIG. 28.

FIG. 30 is an isometric view of the sealing flap, airfoil, and afoam/airflow wall in accordance with one embodiment of the presentinvention.

FIG. 31 is a side section view of a sealing flap and pendulum inaccordance with one embodiment of the present invention.

FIG. 32 is an isometric view of a foam blocking wall within theintegrated tank in accordance with one embodiment of the presentinvention.

FIG. 33 depicts a schematic exploded view of a nose wheel module inaccordance with one embodiment of the present invention.

FIG. 34 depicts a side view of the nose wheel module of FIG. 33.

FIG. 35 depicts a front view of the nose wheel module of FIG. 33.

FIG. 36 depicts a series of maintenance steps for maintaining andservicing a embodiment of the robot of the present invention.

FIGS. 37-41 depict a steps of robot maintenance as identified in FIG.36.

FIG. 42 depicts a side schematic view of a cleaning head and squeegee inaccordance with another embodiment of the present invention.

FIG. 43 depicts a perspective view of the cleaning head and squeegeedepicted in FIG. 42.

FIG. 44 depicts another side schematic view of the cleaning head andsqueegee depicted in FIG. 42.

FIG. 45 depicts a third side schematic view of the cleaning head andsqueegee depicted in FIG. 42.

FIG. 46 depicts a cleaning path for a mobile robot in accordance withone embodiment of the present invention.

FIG. 47 depicts a mobile robot having left and right drive wheelspositioned along a central diameter of the chassis, in accordance withone embodiment of the invention.

FIG. 48 depicts a mobile robot having left and right drive wheelspositioned on the aft bottom portion of the chassis, in accordance withanother embodiment of the invention.

FIG. 49 depicts an offset diameter robot positioned a distance d from awall.

FIG. 50 depicts a control sequence for turning a robot with respect to awall.

FIG. 51 depicts a first phase of a sequence for estimating a wall angle,in accordance with one embodiment of the invention.

FIG. 52 depicts a second phase of a sequence for estimating a wallangle, in accordance with one embodiment of the invention.

FIG. 53 depicts an obstacle avoidance sequence, in accordance with oneembodiment of the invention, for backing a robot away from an obstacle.

FIG. 54 depicts a panic spin sequence for a mobile robot, in accordancewith one embodiment of the invention.

FIG. 55 depicts a wheel drop response sequence for a mobile robot, inaccordance with one embodiment of the invention.

FIG. 56 depicts one embodiment of a brush control sequence in accordancewith a wet cleaning mobile robot.

FIG. 57 depicts a graph of current drawn by a robot motor versus timeover at least one rotation cycle.

FIG. 58 depicts one embodiment of a sequence for pseudo-autocorrelationfor a pump control process for a wet cleaning mobile robot.

FIG. 59 depicts one embodiment of a sequence for implementing a stuckbehavior for a wet cleaning robot.

FIG. 60 depicts one embodiment of a fluid sensing circuit diagram for awet cleaning mobile robot.

FIG. 61A depicts one commercial embodiment of the robot of the presentinvention, including accessories.

FIG. 61B depicts various views of one commercial embodiment of the robotof the present invention.

FIG. 62 depicts one embodiment of a control panel and user interfaceused with one embodiment of the robot.

FIG. 63 depicts another embodiment of a control panel and user interfaceused with one embodiment of the robot.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring now to the drawings where like reference numerals identifycorresponding or similar elements throughout the several views, FIG. 1depicts an isometric view showing the external surfaces of an autonomouscleaning robot 100 according to a preferred embodiment of the presentinvention. The robot 100 is configured with a cylindrical volume havinga generally circular cross-section 102 with a top surface and a bottomsurface that is substantially parallel and opposed to the top surface.The circular cross-section 102 is defined by three mutuallyperpendicular axes; a central vertical axis 104, a fore-aft axis 106,and a transverse axis 108. The robot 100 is movably supported withrespect to a surface to be cleaned, hereinafter, the cleaning surface.The cleaning surface is substantially horizontal.

The robot 100 is generally supported in rolling contact with thecleaning surface by a plurality of wheels or other rolling elementsattached to a chassis 200. In a preferred embodiment, the fore-aft axis108 defines a transport axis along which the robot is advanced over thecleaning surface. The robot is generally advanced in a forward or foretravel direction, designated F, during cleaning operations. The oppositetravel direction, (i.e. opposed by 180°), is designated A for aft. Therobot is generally not advanced in the aft direction during cleaningoperations but may be advanced in the aft direction to avoid an objector maneuver out of a corner or the like. Cleaning operations maycontinue or be suspended during aft transport. The transverse axis 108is further defined by the labels R for right and L for left, as viewedfrom the top view of FIG. 1. In subsequent figures, the R and Ldirection remain consistent with the top view, but may be reversed onthe printed page. In a preferred embodiment of the present invention,the diameter of the robot circular cross-section 102 is approximately370 mm (14.57 inches) and the height of the robot 100 above the cleaningsurface of approximately 85 mm (3.3 inches). However, the autonomouscleaning robot 100 of the present invention may be built with othercross-sectional diameter and height dimensions, as well as with othercross-sectional shapes, e.g. square, rectangular and triangular, andvolumetric shapes, e.g. cube, bar, and pyramidal.

The robot 100 may include a user input control panel, not shown,disposed on an external surface, e.g. the top surface, with one or moreuser manipulated actuators disposed on the control panel. Actuation of acontrol panel actuator by a user generates an electrical signal, whichis interpreted to initiate a command. The control panel may also includeone or more mode status indicators such as visual or audio indicatorsperceptible by a user. In one example, a user may set the robot onto thecleaning surface and actuate a control panel actuator to start acleaning operation. In another example, a user may actuate a controlpanel actuator to stop a cleaning operation.

FIG. 21 shows the four main modules substantially as they are normallyarranged: a tank 800, a top, a battery 201, a robot body 200, and acleaning head 600 within the robot body 200. The robot itself supportsthe battery 201 in a battery socket, and an integrated tank 800 issupported on top of both the robot and the battery 201. The internallower surface of the tank 800 and the internal upper surface of therobot body 200 are configured to substantially conform with the shape ofthe battery 201. As discussed herein, the battery 201 may be replaced bylevering the tank 800 on its pivot but not necessarily lifting orremoving the tank 800. Additionally, as shown in FIG. 21, the cleaninghead 600 may be inserted from the right side of the robot in a slidingmotion without removing the tank 800 or battery 201, and in thisconfiguration may be removed from the robot body 200 for cleaning in themiddle of a cleaning cycle or otherwise. FIG. 21 also shows the controlpanel 330 for the robot, which is detailed below.

As shown in FIG. 21, the tank 800 has a handle as described herein indetail, which has a detent click lock, slightly lifts from the tank whenlifted, and otherwise as described. When the tank 800 is mounted to thebody 200, this handle is for the entire robot. When the tank 800 isdetached from the robot, this handle is for the tank 800 alone. However,a second handle is formed in the robot body, as shown in FIG. 21, anindentation underneath the control panel 330. Accordingly, when thetanks 800 and the base unit 200 are separated, each has its own handle.When the tanks 800 and base unit 200 are reintegrated, the main handleserves for carrying both. The same handle is both a latch for tankremoval when pushed in one direction and an interlock against removalwhen it is held in the other direction.

Exemplary Cleaning Systems

Referring now to FIG. 2, the autonomous robot 100 includes a pluralityof cleaning modules supported on a chassis 200 for cleaning thesubstantially horizontal cleaning surface as the robot is transportedover the cleaning surface. The cleaning modules extend below the robotchassis 200 to contact or otherwise operate on the cleaning surfaceduring cleaning operations. More specifically, the robot 100 isconfigured with a first cleaning zone A for collecting looseparticulates from the cleaning surface and for storing the looseparticulates in a receptacle carried by the robot. The robot 100 isfurther configured with a second cleaning zone B that at least applies acleaning fluid onto the cleaning surface. The cleaning fluid may beclean water alone or clean water mixed with other ingredients to enhancecleaning. The application of the cleaning fluid serves to dissolve,emulsify or otherwise react with contaminants on the cleaning surface toseparate contaminants therefrom. Contaminants may become suspended orotherwise combined with the cleaning fluid. After the cleaning fluid hasbeen applied onto the surface, it mixes with contaminants and becomeswaste material, e.g. a liquid waste material with contaminants suspendedor otherwise contained therein.

The underside of the robot 100 is shown in FIG. 2 which depicts a firstcleaning zone A disposed forward of the second cleaning zone B withrespect to the fore-aft axis 106. Accordingly, the first cleaning zone Aprecedes the second cleaning zone B over the cleaning surface when therobot 100 travels in the forward direction. The first and secondcleaning zones are configured with a cleaning width W that is generallyoriented parallel or nearly parallel with the transverse axis 108. Thecleaning width W defines the cleaning width or cleaning footprint of therobot. As the robot 100 advances over the cleaning surface in theforward direction, the cleaning width is the width of cleaning surfacecleaned by the robot in a single pass. Ideally, the cleaning widthextends across the full transverse width of the robot 100 to optimizecleaning efficiency; however, in a practical implementation, thecleaning width is slightly narrower that the robot transverse width dueto spatial constraints on the robot chassis 200.

According to the present invention, the robot 100 traverses the cleaningsurface in a forward direction over a cleaning path with both cleaningzones operating simultaneously. In a preferred embodiment, the nominalforward velocity of the robot is approximately 4.75 inches per secondhowever; the robot and cleaning devices may be configured to clean atfaster and slower forward velocities. In order to cover a room inadequate time, the range of reasonable velocities is approximately 2 to10 inches per second. The first cleaning zone A precedes the secondcleaning zone B over the cleaning surface and collects looseparticulates from the cleaning surface across the cleaning width W. Thesecond cleaning zone B applies cleaning fluid onto the cleaning surfaceacross the cleaning width W. The second cleaning zone may also beconfigured to smear the cleaning fluid applied onto the cleaning surfaceto smooth the cleaning fluid into a more uniform layer and to mix thecleaning fluid with contaminants on the cleaning surface. The secondcleaning zone B may also be configured to scrub the cleaning surfaceacross the cleaning width. The scrubbing action agitates the cleaningfluid to mix it with contaminants. The scrubbing action also applies ashearing force against contaminants to thereby dislodge contaminantsfrom the cleaning surface. The second cleaning zone B may also beconfigured to collect waste liquid from cleaning surface across thecleaning width. According to the invention, a single pass of the robotover a cleaning path first collects loose particulates up from thecleaning surface across the cleaning width and thereafter applies acleaning fluid onto the cleaning surface generally across the cleaningwidth W to interact with contaminants remaining on the cleaning surfaceand may further apply a scrubbing action to dislodge contaminants fromthe cleaning surface. A single pass of the robot 100 over a cleaningpath may also smear the cleaning fluid more uniformly on the cleaningsurface. A single pass of the robot over a cleaning path may alsocollect waste liquid up from the cleaning surface. The robot may,however, be designed to leave a certain amount of fluid behind on eachpass or on some passes (e.g., to provide time for the cleaning liquid towork on dried material or stubborn stains).

In general, the cleaning robot 100 is configured to clean uncarpetedindoor hard floor surface, e.g. floors covered with tiles, wood, vinyl,linoleum, smooth stone or concrete and other manufactured floor coveringlayers that are not overly abrasive and that do not readily absorbliquid. Other embodiments, however, may be adapted to clean, process,treat, or otherwise traverse abrasive, liquid-absorbing, and othersurfaces. In addition, in a preferred embodiment of the presentinvention, the robot 100 is configured to autonomously transport overthe floors of small enclosed furnished rooms such as are typical ofresidential homes and smaller commercial establishments. The robot 100is not required to operate over predefined cleaning paths but may moveover substantially all of the cleaning surface area under the control ofvarious transport algorithms designed to operate irrespective of theenclosure shape or obstacle distribution. In particular, the robot 100of the present invention moves over cleaning paths in accordance withpreprogrammed procedures implemented in hardware, software, firmware, orcombinations thereof to implement a variety of modes, such as threebasic operational modes, i.e., movement patterns, that can becategorized as: (1) a “spot-coverage” mode; (2) a “wall/obstaclefollowing” mode; and (3) a “bounce” mode. In addition, the robot 100 ispreprogrammed to initiate actions based upon signals received fromsensors incorporated therein, where such actions include, but are notlimited to, implementing one of the movement patterns above, anemergency stop of the robot 100, or issuing an audible alert. Theseoperational modes of the robot of the present invention are specificallydescribed in U.S. Pat. No. 6,809,490, by Jones et al., entitled, Methodand System for Multi-Mode Coverage for an Autonomous Robot, the entiredisclosure of which is herein incorporated by reference it its entirety.However, the present disclosure also describes alternative operationalmodes.

In one embodiment, the robot 100 is configured to clean approximately150 square feet of cleaning surface in a single cleaning operation. Alarger or smaller tank may permit this to range from 100 square feet to400 square feet. The duration of the cleaning operation is approximately45 minutes in certain embodiments. The example of 45 minutes is with asingle battery. In embodiments with smaller, larger, or 2 or morebatteries on board, the cleaning time may range from about 20 minutes toup to about 2 hours. Accordingly, the robot systems are configured(physically, and as programmed) for unattended autonomous cleaning for45 minutes or more without the need to recharge a power supply, refillthe supply of cleaning fluid or empty the waste materials collected bythe robot. Although certain embodiments of the robot are designed for asmall area rooms, there is no minimum square footage or cleaning time. Arobot according to the invention could be configured with a tank ofvirtually any size.

As shown in FIGS. 2 and 3 the robot 100 includes a plurality ofsubsystems mounted to a robot chassis 200. The major robot subsystemsare shown schematically in FIG. 4 which depicts a master control module300 interconnected for two-way communication with each of a plurality ofother robot subsystems. The interconnection of the robot subsystems isprovided via network of interconnected wires and or conductive elements,e.g. conductive paths formed on an integrated printed circuit board orthe like, as is well known. The master control module 300 at leastincludes a programmable or preprogrammed digital data processor, e.g. amicroprocessor, for performing program steps, algorithms and ormathematical and logical operations as may be required. The mastercontrol module 300 also includes a digital data memory in communicationwith the data processor for storing program steps and other digital datatherein. The master control module 300 also includes one or more clockelements for generating timing signals as may be required.

A power module 310 delivers electrical power to all of the major robotsubsystems. The power module includes a self-contained power sourceattached to the robot chassis 200, e.g. a rechargeable battery, such asa nickel metal hydride battery, or the like. In addition, the powersource is configured to be recharged by any one of various rechargingelements and or recharging modes, or the battery may be replaced by auser when it becomes discharged or unusable. The master control module300 may also interface with the power module 310 to control thedistribution of power, to monitor power use and to initiate powerconservation modes as required.

The robot 100 may also include one or more interface modules or elements320. Each interface module 320 is attached to the robot chassis toprovide an interconnecting element or port for interconnecting with oneor more external devices. Interconnecting elements and ports arepreferably accessible on an external surface of the robot. The mastercontrol module 300 may also interface with the interface modules 320 tocontrol the interaction of the robot 100 with an external device. Inparticular, one interface module element is provided for charging therechargeable battery via an external power supply or power source suchas a conventional AC or DC power outlet. Another interface moduleelement may be configured for one or two way communications over awireless network and further interface module elements may be configuredto interface with one or more mechanical devices to exchange liquids andloose particulates therewith, e.g. for filling a cleaning fluidreservoir or for draining or emptying a waste material container.

Accordingly, the interface module 320 may comprise a plurality ofinterface ports and connecting elements for interfacing with activeexternal elements for exchanging operating commands, digital data andother electrical signals therewith. The interface module 320 may furtherinterface with one or more mechanical devices for exchanging liquid andor solid materials therewith. The interface module 320 may alsointerface with an external power supply for charging the robot powermodule 310. Active external devices for interfacing with the robot 100may include, but are not limited to, a floor standing docking station, ahand held remote control device, a local or remote computer, a modem, aportable memory device for exchanging code and or data with the robotand a network interface for interfacing the robot 100 with any deviceconnected to the network. In addition, the interface module 320 mayinclude passive elements such as hooks and or latching mechanisms forattaching the robot 100 to a wall for storage or for attaching the robotto a carrying case or the like.

In particular, an active external device according to one aspect of thepresent invention confines the robot 100 in a cleaning space such as aroom by emitting radiation in a virtual wall pattern. The robot 100 isconfigured to detect the virtual wall pattern and is programmed to treatthe virtual wall pattern as a room wall so that the robot does not passthrough the virtual wall pattern. This particular aspect of the presentinvention is specifically described in U.S. Pat. No. 6,690,134 by Joneset al., entitled Method and System for Robot Localization andConfinement, the entire disclosure of which is herein incorporated byreference it its entirety.

Another active external device according to a further aspect of thepresent invention comprises a robot base station used to interface withthe robot. The base station may comprise a fixed unit connected with ahousehold power supply, e.g. and AC power wall outlet and or otherhousehold facilities such as a water supply pipe, a waste drain pipe anda network interface. According to invention, the robot 100 and the basestation are each configured for autonomous docking and the base stationmay be further configured to charge the robot power module 310 and toservice the robot in other ways. A base station and autonomous robotconfigured for autonomous docking and for recharging the robot powermodule is specifically described in U.S. patent application Ser. No.10/762,219, by Cohen, et al., filed on Jan. 21, 2004, entitledAutonomous Robot Auto-Docking and Energy Management Systems and Methods,the entire disclosure of which is herein incorporated by reference itits entirety.

The autonomous robot 100 includes a self-contained motive transportdrive subsystem 900 which is further detailed below. The transport drive900 includes three wheels extending below the chassis 200 to providethree points of rolling support with respect to the cleaning surface. Anose wheel is attached to the robot chassis 200 at a forward edgethereof, coaxial with the fore-aft axis 106, and a pair of drive wheelsattached to the chassis 200 aft of the transverse axis 108 and rotatableabout a drive axis that is parallel with the transverse axis 108. Eachdrive wheel is separately driven and controlled to advance the robot ina desired direction. In addition, each drive wheel is configured toprovide sufficient drive friction as the robot operates on a cleaningsurface that is wet with cleaning fluid. The nose wheel is configured toself align with the direction of travel. The drive wheels may becontrolled to move the robot 100 forward or aft in a straight line oralong an arcuate path.

The robot 100 further includes a sensor module 340. The sensor module340 comprises a plurality of sensors attached to the chassis and orintegrated with robot subsystems for sensing external conditions and forsensing internal conditions. In response to sensing various conditions,the sensor module 340 may generate electrical signals and communicatethe electrical signals to the control module 300. Individual sensors mayperform such functions as detecting walls and other obstacles, detectingdrop offs in the cleaning surface, called cliffs, detecting dirt on thefloor, detecting low battery power, detecting an empty cleaning fluidcontainer, detecting a full waste container, measuring or detectingdrive wheel velocity distance traveled or slippage, detecting nose wheelrotation or cliff drop off, detecting cleaning system problems suchrotating brush stalls or vacuum system clogs, detecting inefficientcleaning, cleaning surface type, system status, temperature, and manyother conditions. In particular, several aspects of the sensor module340 of the present invention as well as and its operation, especially asit relates to sensing external elements and conditions are specificallydescribed in U.S. Pat. No. 6,594,844, by Jones, entitled Robot ObstacleDetection System, and U.S. patent application Ser. No. 11/166,986, byCasey et al., filed on Jun. 24, 2005, entitled Obstacle Following SensorScheme for a Mobile Robot, the entire disclosures of which are hereinincorporated by reference it their entireties.

One difference between the present robot and either the dry vacuum robotor the large industrial cleaner is the proximity of the control andsensor components to the wet cleaning components. In most dry vacuumingrobots, none of the sensors or control elements are prone to being wetby water or by more damaging cleaning fluids or solvents, because no wetcleaners are used and no waste fluid is generated. With a largeindustrial cleaner, the controls and sensors can be placed as far asnecessary from the cleaning elements, perhaps a few feet away, and theonly sensors that need accommodate wetness are those for sensing fluidlevels.

The present invention is contemplated for household use (commercial andindustrial use is also contemplated, but these environments may requirelarger versions of the robot). Accordingly, a household robot should besmall and squat, e.g., less than 4 inches from the ground, and around afoot in diameter. Much of the volume is occupied by fluid brushing,spinning, spraying, and blowing devices, and fluid and/or foampenetrates most parts of the robot at one time or another. At most, thecontrol and sensor electronics will be a few inches from the nearestfluid or foam torrent.

Accordingly, the invention contemplates that the entire main controlboard will be fluid sealed, either in a water resistant or waterproofhousing having at least JIS grade 3 (mild spray) water/fluid resistance,but grade 5 (strong spray) and grade 7 (temporary immersion) are alsodesirable. The main control board should be sealed in a JIS grade 3-7housing (1) by a screwed-down and gasketed cover over the main housing;(2) by a welded, caulked, sealed, or glued cover secured to the mainhousing; (3) by being pre-assembled in a water resistant, water-tight,water-proof, or hermetically sealed compartment or module; or (4) bybeing positioned in a volume suitable for potting or pre-potted in resinor the like.

Many sensor elements have a local small circuit board, sometimes with alocal microprocessor and/or A/D converter and the like, and thesecomponents are often sensitive to fluids and corrosion. The inventionalso contemplates that any sensor circuit boards distributed throughoutthe body of the robot will also be sealed in a JIS grade 3-7 housing ina similar manner. The invention also contemplates that multiple circuitboards, including at least the main circuit board and one remote circuitboard several inches from the main board, may be sealed by a singlematching housing or cover. For example, all or some of the circuitboards could be arranged in a single plastic or resin module havingextensions which reach to local sensor sites, and a distributed covercould be secured over all of the circuit boards. In addition, exposedelectrical connections and terminals of sensors, motors, orcommunication lines can be sealed in a similar manner, with covers,modules, potting, shrink fit, gaskets, or the like. In this manner,substantially the entire electrical system is fluid-sealed and/orisolated from spraying or foaming liquid. Any and all electrical orelectronic elements defined herein as a circuit board, PCB, detector,sensor, etc., are candidates for such sealing.

The robot 100 may also include a user control module 330. The usercontrol module 330 provides one or more user input interfaces thatgenerate an electrical signal in response to a user input andcommunicate the signal to the master control module 300. In oneembodiment of the present invention, the user control module, describedabove, provides a user input interface, however, a user may entercommands via a hand held remote control device, a programmable computeror other programmable device or via voice commands. A user may inputuser commands to initiate actions such as power on/off, start, stop orto change a cleaning mode, set a cleaning duration, program cleaningparameters such as start time and duration, and or many other userinitiated commands. User input commands, functions, and componentscontemplated for use with the present invention are specificallydescribed in U.S. patent application Ser. No. 11/166,891, by Dubrovskyet al., filed on Jun. 24, 2005, entitled Remote Control Scheduler andMethod for Autonomous Robotic Device, the entire disclosure of which isherein incorporated by reference it its entirety. Specific modes of userinteraction are also described herein.

Cleaning Zones

Referring now to FIG. 2, a bottom surface of a robot chassis 200 isshown in isometric view. As shown therein, a first cleaning zone A isdisposed forward of a second cleaning zone B with respect to thefore-aft axis 106. Accordingly, as the robot 100 is transported in theforward direction the first cleaning zone A precedes the second cleaningzone B over the cleaning surface. Each cleaning zone A and B has acleaning width W disposed generally parallel with the transverse axis108. Ideally, the cleaning width of each cleaning zone is substantiallyidentical however, the actual cleaning width of the cleaning zones A andB may be slightly different. According to a preferred embodiment of thepresent invention, the cleaning width W is primarily defined by thesecond cleaning zone B which extends from proximate to the rightcircumferential edge of a bottom surface of the robot chassis 200substantially parallel with the transverse axis 108 and is approximately296 mm or 11.7 inches long, i.e., approximately 30 cm or 12 inches long.By locating the cleaning zone B proximate the right circumferentialedge, the robot 100 may maneuver its right circumferential edge close toa wall or other obstacle for cleaning the cleaning surface adjacent tothe wall or obstacle. Accordingly, the robot movement patterns includealgorithms for transporting the right side of the robot 100 adjacent toeach wall or obstacle encountered by the robot during a cleaning cycle.The robot 100 is therefore said to have a dominant right side. Ofcourse, the robot 100 could be configured with a dominant left sideinstead. The first cleaning zone A is positioned forward of thetransverse axis 108 and has a slightly narrower cleaning width than thesecond cleaning zone B, simply because of the circumference shape of therobot 100. However, any cleaning surface area not cleaned by the firstcleaning zone A is cleaned by the second cleaning zone B.

First Cleaning Zone or Dry Vacuum Cleaning

The first cleaning zone A is configured to collect loose particulatesfrom the cleaning surface. In a preferred embodiment, an air jet isgenerated by an air moving system which includes an air jet port 554disposed on a left edge of the first cleaning zone A. The air jet port554 expels a continuous jet or stream of pressurized air therefrom. Theair jet port 554 is oriented to direct the air jet across the cleaningwidth from left to right. Opposed to the air jet port 554, an air intakeport 556 is disposed on a right edge of the first cleaning zone A. “Airintake port” as used herein may mean “vacuum port,” “air inlet,”“negative pressure zone,” etc. The air moving system generates anegative air pressure zone in the conduits connected to the intake port556, which creates a negative air pressure zone proximate to the intakeport 556. The negative air pressure zone suctions loose particulates andair into the air intake port 556 and the air moving system is furtherconfigured to deposit the loose particulates into a waste materialcontainer carried by the robot 100. Accordingly, pressurized airexpelled from the air jet port 554 moves across the cleaning widthwithin the first cleaning zone A and forces loose particulates on thecleaning surface toward a negative air pressure zone proximate to theair intake port 556. The loose particulates are suctioned up from thecleaning surface through the air intake port 556 and deposited into awaste container carried by the robot 100. The first cleaning zone A isfurther defined by a nearly rectangular channel formed between the airjet port 554 and the air intake port 556. The channel is defined byopposing forward and aft walls of a rectangular recessed area 574, whichis a contoured shape formed in the bottom surface of the robot chassis200. The forward and aft walls are substantially transverse to thefore-aft axis 106. The channel is further defined by a first compliant“doctor” (air flow guide) blade 576, attached to the robot chassis 200,e.g. along the aft edge of the recessed area 574, and extending from thechassis bottom surface to the cleaning surface.

The doctor air flow guide blade is mounted to make contact or nearcontact with the cleaning surface. The doctor air flow guide blade 576is preferably formed from a thin flexible and compliant molded materiale.g. a 1-2 mm thick bar shaped element molded from neoprene rubber orthe like. The doctor air flow guide blade 576, or at least a portion ofthe doctor air flow guide blade, may be coated with a low frictionmaterial, e.g. a fluoropolymer resin for reducing friction between thedoctor air flow guide blade and the cleaning surface. The doctor airflow guide blade 576 may be attached to the robot chassis 200 by anadhesive bond or by other suitable means. Air guide blade 576, towardthe rear of the robot, is angled with respect to the direction oftravel, by about 95-120 degrees from the direction of travel. The end ofthe blade 576 nearest the vacuum port 556 is farther toward the rear.Accordingly, debris will tend to move along the angled blade 576 as therobot moves forward. As depicted in FIG. 2, angled guide blade 578points substantially toward the vacuum intake in such a manner that thevacuum intake also draws air and debris along the forward side of thesmaller angled guide blade 578. The small dry vacuum blade is positionedto divert lighter objects, that would otherwise been blown past thesuction port, back towards the suction port to be injected. It alsodirects larger objects back towards this port.

The forward caster wheel, as shown in FIG. 2 near the front of therobot, is generally restricted to 180 degrees of side to side travel.Certain embodiments may, however, benefit from larger ranges of motion.For example, the criteria for certain embodiments of the forward casteris either 360 degrees (free movement), or less than 180 degrees (limitedbut reversible movement), but is typically 160-170 degrees forcommercial embodiments. Certain ranges of motion of the caster wheel maycause the wheel to lock up when in reverse travel.

The channel of the first cleaning zone A provides an increased volumebetween the cleaning surface and the bottom surface of the robot chassis200 local to the first cleaning zone A. The increased volume guidesairflow between the jet port 554 and the air intake port 556, and thedoctor air flow guide blade 576 prevents loose particulates and airflowfrom escaping the first cleaning zone A in the aft direction. Inaddition to guiding the air jet and the loose particulates across thecleaning width, the first doctor air flow guide blade 576 may also exerta friction force against contaminants on the cleaning surface to helploosen contaminants from the cleaning surface as the robot moves in theforward direction. The first compliant doctor air flow guide blade 576is configured to be sufficiently compliant to adapt its profile formconforming to discontinuities in the cleaning surface, such a door jams,moldings, and trim pieces, without hindering the forward travel of therobot 100.

A second compliant doctor air flow guide blade 578 may also be disposedin the first cleaning zone A to further guide the air jet toward thenegative pressure zone surrounding the air intake port 554. The secondcompliant doctor air flow guide blade is similar in construction to thefirst compliant doctor air flow guide blade 576 and attaches to thebottom surface of the robot chassis 200 to further guide the air andloose particulates moving through the channel. In one example, a secondrecessed area 579 is formed in the bottom surface of the chassis 200 andthe second compliant doctor air flow guide blade 576 protrudes into thefirst recessed area 574 at an acute angle typically between 30-60° withrespect to the traverse axis 108. The second compliant air flow guideblade extends from the forward edge of the recessed area 574 andprotrudes into the channel approximately ⅓ to ½ of channel fore-aftdimension.

The first cleaning zone A traverses the cleaning surface along acleaning path and collects loose particulates along the cleaning width.By collecting the loose particulates prior to the second cleaning zone Bpassing over the cleaning path, the loose particulates are collectedbefore the second cleaning zone applies cleaning fluid onto the cleaningsurface. One advantage of removing the loose particulates with the firstcleaning zone is that the loose particulates are removed while they arestill dry. Once the loose particulates absorb cleaning fluid applied bythe second cleaning zone, they are more difficult to collect. Moreover,the cleaning fluid absorbed by the loose particulates is not availablefor cleaning the surface so the cleaning efficiency of the secondcleaning zone B may be degraded. The first cleaning zone generally savesa user the task of sweeping before mopping, and is generally apre-treatment. However, in an alternative configuration, the firstcleaning zone is a dry vacuum that may operate separate and apart fromthe wet-cleaning functionality of the robot. Still further, in such acase, the first cleaning zone may be provided with a rotating brush orcounter-rotating brushes, or may use brushes only rather than a brushand vacuum.

In another embodiment, the first cleaning zone may be configured withother cleaning elements such as counter-rotating brushes extendingacross the cleaning width to flick loose particulates into a receptacle.In another embodiment, an air moving system may be configured to drawair and loose particulates up from the cleaning surface through anelongated air intake port extending across the cleaning width. Inparticular, other embodiments usable to provide a first cleaning zoneaccording to the present invention are disclosed in U.S. Pat. No.6,883,201, by Jones et al. entitled Autonomous Floor-Cleaning Robot, theentire disclosure of which is herein incorporated by reference it itsentirety.

FIG. 22 depicts elements similar to those depicted in FIG. 3. Somealternative terminology is used in the following description. Theelements shown in FIG. 22 are the main electrical board 300, a “cam”driven pump 706, the front caster 960, a stasis circuit board 300 abearing IR “stasis” sensors and components (i.e., that detect when thefront wheel does not rotate along with the driven wheels, indicating therobot may be stuck), a reed switch PCB 300 b, a charging plug PCB 300 cfor receiving a battery charging cord, a battery contact blade 777 forcontact to the battery as it is placed into the robot body, a boardgasket/seal 301 that lines the edge of the board 300 and matches up withthe cover to waterproof the board 300, a bumper 220, the main chassis200, the wet cleaning head motor and drivetrain 608 locatedsubstantially in line with the wet cleaning head, a left drivetrain/wheel assembly 909 (showing biasing springs, suspension,integrated planetary or other gear train), a right drive train/wheelassembly 908 (similarly arranged), a bifurcated dry vacuum duct andexhaust duct 517 a, 517 b, a replaceable filter for the fan assembly(which should have small enough pores and a surface configured toprevent both particulates and most water from entering the fanassembly), a first or left spray nozzle 712, a second or right spraynozzle 714, a nozzle tube for the right spray nozzle, the fan assembly502, the inner cover of the robot main body, and wire clips for securingthe inner cover to the chassis.

The stasis circuit board 300 a, the reed switch PCB 300 b, and thecharging plug 300 c are parts that may or should be rendered waterresistant or water proof by the structures described herein. These PCBs,as shown in FIG. 22, tend to be located to support the associated sensorand electronic parts.

The dry vacuum may be provided with a main cleaning brush to flick dirtinto a small dirt bin. This bin could be mounted forward of the brush oraft (with appropriate modifications to the brush shroud). In addition tocovering the floor with a thin sheet of water, which evaporates andincreases the relative humidity, the ducting for the vacuum exhaust maybe directed to constantly blow air across the water in the dirty orclean tank. The air leaving the dirty or clean tank will tend to havehigher relative humidity than the air entering it, further increasingthe humidity in the room, and if the cleaning fluid has added fragrance,this may be blown into the room.

Second Cleaning Zone or Wet Cleaning Head

The second cleaning zone B includes a liquid applicator 700 (also oralternatively, spray head and/or spreader) configured to apply acleaning fluid onto the cleaning surface and the cleaning fluid ispreferably applied uniformly across the entire cleaning width. Theliquid applicator 700 is attached to the chassis 200 and includes atleast one nozzle configured to spray the cleaning fluid onto thecleaning surface. The second cleaning zone B may also include ascrubbing module 600 (also or alternatively, a powered brush) forperforming other cleaning tasks across the cleaning width after thecleaning fluid has been applied onto the cleaning surface. The scrubbingmodule 600 may include a smearing element disposed across the cleaningwidth for smearing the cleaning fluid to distribute it more uniformly onthe cleaning surface. The second cleaning zone B may also include apassive or active scrubbing element, scrub brush, wiper, or wipe clothconfigured to scrub the cleaning surface across the cleaning width. Thesecond cleaning zone B may also include a second collecting apparatus(also or alternatively, wet vacuum, directed at either a wet surface ora wet brush) configured to collect waste materials up from the cleaningsurface across the cleaning width, and the second collecting apparatusis especially configured for collecting liquid waste materials.

Liquid Applicator Module or Spray Head

The liquid applicator module 700, shown schematically in FIG. 5, isconfigured to apply a measured volume of cleaning fluid onto thecleaning surface across the cleaning width. “Liquid applicator module”as used herein, may mean “nozzle,” “spray head,” and/or “spreaderbrush/wiper.” Additionally, the liquid applicator module may spray thefloor directly, spray a fluid-bearing brush or roller, or apply fluid bydripping or capillary action to the floor, brush, roller, or pad. Theliquid applicator module 700 receives a supply of cleaning fluid from acleaning fluid supply container S, carried on the chassis 200, and pumpsthe cleaning fluid through one or more spray nozzles disposed on thechassis 200. The spray nozzles are attached to the robot chassis 200 aftof the first cleaning zone A and each nozzle is oriented to applycleaning fluid onto the cleaning surface. In a preferred embodiment, apair of spray nozzle are attached to the robot chassis 200 at distalleft and right edges of the cleaning width W. Each nozzle is oriented tospray cleaning fluid toward the opposing end of the cleaning width. Eachnozzles is separately pumped to eject a spray pattern and the pumpingstroke of each nozzle occurs approximately 180 degrees out phase withrespect to the other nozzle so that one of the two nozzles is alwaysapplying cleaning fluid.

Referring to FIG. 5, the liquid applicator module 700 includes acleaning fluid supply container S, which is carried by the chassis 200(and/or a compartment within an integrated tank) and removable therefromby a user to refill the container with cleaning fluid (alternatively,the container S is refilled with water, cleaning concentrate beingsupplied from another compartment or as a solid or powder). The supplycontainer S is configured with a drain or exit aperture 702 formedthrough a base surface thereof. A fluid conduit 704 receives cleaningfluid from the exit aperture 702 and delivers a supply of cleaning fluidto a pump assembly 706. The pump assembly 706 includes left and rightpump portions 708 and 710, driven by a rotating cam, shown in FIG. 7.The left pump portion 708 pumps cleaning fluid to a left spray nozzle712 via a conduit 716 and the right pump portion 710 pumps cleaningfluid to a right spray nozzle 714 via a conduit 718.

A stop valve assembly, shown in section view in FIG. 6, includes afemale upper portion 720, installed inside the supply container S, and amale portion 721 attached to the chassis 200. The female portion 720nominally closes and seals the exit aperture 702. The male portion 721opens the exit aperture 702 to provide access to the cleaning fluidinside the supply container S. The female portion 720 includes an upperhousing 722, a spring biased movable stop 724, a compression spring 726for biasing the stop 724 to a closed position, and a gasket 728 forsealing the exit aperture 702. The upper housing 722 may also support afilter element 730 inside the supply container S for filteringcontaminants from the cleaning fluid before the fluid exits the supplycontainer S.

The stop valve assembly male portion 721 includes a hollow male fitting732 formed to insert into the exit aperture 702 and penetrate the gasket728. Insertion of the hollow male fitting 732 into the exit aperture 702forces the movable stop 724 upward against the compression spring 726 toopen the stop valve. The hollow male fitting 732 is formed with a flowtube 734 along it central longitudinal axis and the flow tube 734includes one or more openings 735 at its uppermost end for receivingcleaning fluid into the flow tube 734. At its lower end, the flow tube734 is in fluid communication with a hose fitting 736 attached to orintegrally formed with the male fitting 732. The hose fitting 736comprises a tube element having a hollow fluid passage 737 passingtherethrough, and attaches to hose or fluid conduit 704 that receivesfluid from the hose fitting 736 and delivers the fluid to the pumpassembly 706. The flow tube 734 may also include a user removable filterelement 739 installed therein for filtering the cleaning fluid as itexits the supply container S.

According to the invention, the stop valve male portion 721 is fixed tothe chassis 200 and engages with the female portion 720, which is fixedto the container S. When the container S is installed onto the chassisin its operating position the male portion 721 engages with the femaleportion 720 to open the exit aperture 702. A supply of cleaning fluidflows from the supply container S to the pump assembly 706 and the flowmay be assisted by gravity or suctioned by the pump assembly or both.

The hose fitting 736 is further equipped with a pair of electricallyconductive elements, not shown, disposed on the internal surface of thehose fitting fluid flow passage 737 and the pair of conductive elementsinside the flow chamber are electrically isolated from each other. Ameasurement circuit, not shown, creates an electrical potentialdifference between the pair of electrically conductive elements and whencleaning fluid is present inside the flow passage 737 current flows fromone electrode to the other through the cleaning fluid and themeasurement circuit senses the current flow. When the container S isempty, the measurement circuit fails to sense the current flow and inresponse sends a supply container empty signal to the master controller300. In response to receiving the supply container empty signal, themaster controller 300 takes an appropriate action.

The pump assembly 706 as depicted in FIG. 5 includes a left pump portion708 and a right pump portion 710. The pump assembly 706 receives acontinuous flow of cleaning fluid from the supply container S andalternately delivers cleaning fluid to the left nozzle 712 and the rightnozzle 714. FIG. 7 depicts the pump assembly 706 in section view and thepump assembly 706 is shown mounted on the top surface of the chassis 200in FIG. 3. The pump assembly 706 includes cam element 738 mounted on amotor drive shaft for rotation about a rotation axis. The motor, notshown, is rotates the cam element 738 at a substantially constantangular velocity under the control of the master controller 300.However, the angular velocity of the cam element 738 may be increased ordecreased to vary the frequency of pumping of the left and right spaynozzles 712 and 714. In particular, the angular velocity of the camelement 738 controls the mass flow rate of cleaning fluid applied ontothe cleanings surface. According to one aspect of the present invention,the angular velocity of the cam element 738 may be adjusted inproportion to the robot forward velocity to apply a uniform volume ofcleaning fluid onto the cleaning surface irrespective of robot velocity.Alternately, changes in the angular velocity in the cam element 738 maybe used to increase or decrease the mass flow rate of cleaning fluidapplied onto the cleanings surface as desired.

The pump assembly 706 includes a rocker element 761 mounted to pivotabout a pivot axis 762. The rocker element 761 includes a pair ofopposed cam follower elements 764 on the left side and 766 on the rightside. Each cam follower 764 and 766 remains in constant contact with acircumferential profile of the cam element 738 as the cam elementrotates about its rotation axis. The rocker element 761 further includesa left pump actuator link 763 and a right pump actuator link 765. Eachpump actuator link 763 and 765 is fixedly attached to a correspondingleft pump chamber actuator nipple 759 and a right pump chamber actuatornipple 758. As will be readily understood, rotation of the cam element738 forces each of the cam follower elements 764 and 766 to follow thecam circumferential profile and the motion dictated by the cam profileis transferred by the rocker element 761 to each of the left and rightactuator nipples 759 and 758. As described below, the motion of theactuator nipples is used to pump cleaning fluid. The cam profile isparticularly shaped to cause the rocker element 761 to force the rightactuator nipple 758 downward while simultaneously lifting up on the leftactuator nipple 759, and this action occurs during the first 180 degreesof cam. Alternately, the second 180 degrees of cam rotation causes therocker element 761 to force the left actuator nipple 759 downward whilesimultaneously lifting up on the right actuator nipple 758.

The rocker element 761 further includes a sensor arm 767 supporting apermanent magnet 769 attached at its end. A magnetic field generated bythe magnet 769 interacts with an electrical circuit 771 supportedproximate to the magnet 769 and the circuit generates signals responsiveto changes in the orientation of magnetic field, the signals are used totrack the operation of the pump assembly 706.

Referring to FIGS. 7-9, the pump assembly 706 further comprises aflexible membrane 744 mounted between opposing upper and lowernonflexible elements 746 and 748 respectively. Referring to the sectionview in FIG. 7 the flexible element 744 is captured between an uppernonflexible element 746 and a lower nonflexible element 748. Each of theupper nonflexible element 746, the flexible element 744 and the lowernonflexible element 748 is formed as a substantially rectangular sheethaving a generally uniform thickness. However, each element alsoincludes patterns of raised ridges depressed valleys and other surfacecontours formed on opposing surfaces thereof. FIG. 8 depicts a top viewof the flexible element 744 and FIG. 9 depicts a top view of the lowernonflexible element 748. The flexible element 744 is formed from aflexible membrane material such as neoprene rubber or the like and thenonflexible elements 748 and 746 are each formed from a stiff materialnonflexible such as moldable hard plastic or the like.

As shown in FIGS. 8 and 9, each of the flexible element 744 and thenonflexible element 748 are symmetrical about a center axis designated Ein the figure. In particular, the left sides of each of the elements746, 744 and 748 combine to form a left pump portion and the rights sideof each of the elements 746, 744 and 748 combine to form a right pumpportion. The left and right pump portions are substantially identical.When the three elements are assembled together, the raised ridges,depressed valleys and surface contours of each element cooperate withraised ridges depressed valleys and surface contours of the contactingsurfaces of other of the elements to create fluid wells and passageways.The wells and passageways may be formed between the upper element 746and the flexible element 744 or between the lower nonflexible element748 and the flexible element 744. In general, the flexible element 744serves as a gasket layer for sealing the wells and passages and itsflexibility is used to react to changes in pressure to seal and or openpassages in response to local pressure changes as the pump operates. Inaddition, holes formed through the elements allow fluid to flow in andout of the pump assembly and to flow through the flexible element 744.

Using the right pump portion by way of example, cleaning fluid is drawninto the pump assembly through an aperture 765 formed in the center ofthe lower nonflexible element 748. The aperture 765 receives cleaningfluid from the fluid supply container via the conduit 704. The incomingfluid fills a passageway 766. Ridges 775 and 768 form a valley betweenthem and a mating raised ridge on the flexible 744 fills the valleybetween the ridges 775 and 768. This confines the fluid within thepassageway 766 and pressure seal the passageway. An aperture 774 passesthrough the flexible element 744 and is in fluid communication with thepassageway 766. When the pump chamber, described below, expands, theexpansion decreases the local pressure, which draws fluid into thepassageway 776 through the aperture 774.

Fluid drawn through the aperture 774 fills a well 772. The well 772 isformed between the flexible element 744 and the upper nonflexibleelement 746. A ridge 770 surrounds the well 772 and mates with a featureof the upper flexible element 746 to contain the fluid in the well 772and to pressure seal the well. The surface of the well 772 is flexiblesuch that when the pressure within the well 772 decreases, the base ofthe well is lifted to open the aperture 774 and draw fluid through theaperture 774. However, when the pressure within the well 772 increases,due to contraction of the pump chamber, the aperture 774 is forcedagainst a raised stop surface 773 directly aligned with the aperture andthe well 772 act as a trap valve. A second aperture 776 passes throughthe flexible element 744 to allow fluid to pass from the well 772through the flexible element 744 and into a pump chamber. The pumpchamber is formed between the flexible element 744 and the lowernonflexible element 748.

Referring to FIG. 7, a right pump chamber 752 is shown in section view.The chamber 752 includes a dome shaped flexure formed by an annular loop756. The dome shaped flexure is a surface contour of the flexibleelement 744. The annular loop 756 passes through a large aperture 760formed through the upper nonflexible element 746. The volume of the pumpchamber is expanded when the pump actuator 765 pulls up on the actuatornipple 758. The volume expansion decreases pressure within the pumpchamber and fluid is drawn into the chamber from the well 772. Thevolume of the pump chamber is decreased when the pump actuator 765pushes down on the actuator nipple 758. The decrease in volume withinthe chamber increases pressure and the increased pressure expels fluidout of the pump chamber.

The pump chamber is further defined by a well 780 formed in the lowernonflexible element 748. The well 780 is surrounded by a valley 784formed in the lower nonflexible element 748, shown in FIG. 9, and aridge 778 formed on the flexible element 744 mates with the valley 784to pressure seal the pump chamber. The pump chamber 752 further includesan exit aperture 782 formed through the lower nonflexible element 748and through which fluid is expelled. The exit aperture 782 deliversfluid to the right nozzle 714 via the conduit 718. The exit aperture 782is also opposed to a stop surface which acts as a check valve to closethe exit aperture 782 when the pump chamber is decreased.

Thus according to the present invention, cleaning fluid is drawn from acleaning supply container S by action of the pump assembly 706. The pumpassembly 706 comprises two separate pump chambers for pumping cleaningfluid to two separate spray nozzles. Each pump chamber is configured todeliver cleaning fluid to a single nozzle in response to a rapidincrease in pressure inside the pump chamber. The pressure inside thepump chamber is dictated by the cam profile, which is formed to drivefluid to each nozzle in order to spray a substantially uniform layer ofcleaning fluid onto the cleaning surface. In particular, the cam profileis configured to deliver a substantially uniform volume of cleaningfluid per unit length of cleaning width W. In generally, the liquidapplicator of the present invention is configured to apply cleaningfluid at a volumetric rate ranging from about 0.2 to 5.0 ml per squarefoot, and preferably in the range of about 0.6-2.0 ml per square foot.However depending upon the application, the liquid applicator of thepresent invention may apply any desired volumetric layer onto thesurface. In addition, the fluid applicator system of the presentinvention is usable to apply other liquids onto a floor surface such aswax, paint, disinfectant, chemical coatings, and the like.

As is further described below, a user may remove the supply container Sfrom the robot chassis and fill the supply container with a measuredvolume of clean water and a corresponding measured volume of a cleaningagent. The water and cleaning agent may be poured into the supplycontainer S through a supply container access aperture 168 which iscapped by a removable cap 172, shown in FIG. 17. The supply container Sis configured with a liquid volume capacity of approximately 1100 ml (37fluid ounces) and the desired volumes of cleaning agent and clean watermay be poured into the supply tank in a ratio appropriate for aparticular cleaning application.

Scrubbing Module, Powered Brush and/or Powered Wiper

The scrubbing module 600, according to a preferred embodiment of thepresent invention, is shown in exploded isometric view in FIG. 10 and inthe robot bottom view shown in FIG. 2. The scrubbing module 600 may beconfigured as a separate subassembly that attaches to the chassis 200but is removable therefrom, by a user, for cleaning or otherwiseservicing the cleaning elements thereof. Other arrangements can beconfigured without deviating from the present invention. For example, inan alternate configuration, the upper wall of the scrubbing module 600would be essentially part of/integral with the robot main body, but thescrubbing module would open as shown to permit cleaning of brush,squeegee, and internal cavity (in such a case, “scrubbing module”remains appropriate terminology). A readily removable scrubbing modulemay be referred to as a “cartridge,” e.g., scrubbing cartridge orcleaning head cartridge. The scrubbing module 600 installs and latchesinto place within a hollow cavity 602, formed on the bottom side of thechassis 200. A profile of the hollow cavity 602 is displayed on theright side of the chassis 200 in FIG. 3. The cleaning elements of thescrubbing module 600 are positioned aft of the liquid applicator module700 to perform cleaning operations on a wet cleaning surface.

In a preferred embodiment, the scrubbing module 600 includes a passivesmearing or spreading element (also, and alternatively, “spreader” or“spreader brush”) 612 attached to a forward edge thereof and disposedacross the cleaning width. The smearing or spreader brush 612 extendsdownwardly from the scrubbing module 600 and is configured to makecontact or near contact with the cleaning surface across the cleaningwidth. As the robot 100 is transported in the forward direction thesmearing brush 612 moves over the pattern of cleaning fluid applied downby the liquid applicator and smears, or more uniformly spreads thecleaning fluid over the cleaning surface. The smearing or spreader brush612, shown in FIGS. 2 and 10, comprises a plurality of soft compliantsmearing bristles 614 with a first end of each bristle being captured ina holder such as crimped metal channel, or other suitable holdingelement. A second end of each smearing bristle 614 is free to bend aseach bristle makes contact with the cleaning surface. The length anddiameter of the smearing or spreader bristles 614, as well as a nominalinterference dimension that the smearing bristles makes with respect tothe cleaning surface may be varied to adjust bristle stiffness and tothereby affect the smearing action. In a preferred embodiment of thepresent invention the smearing or spreader 612 comprises nylon bristleswith an average bristle diameter in the range of about 0.05-0.2 mm(0.002-0.008 inches). The nominal length of each bristle 614 isapproximately 16 mm (0.62 inches) between the holder and the cleaningsurface and the bristles 614 are configured with an interferencedimension of approximately 0.75 mm (0.03 inches). The smearing brush 612may also wick up excess cleaning fluid applied to the cleaning surfaceand distribute the wicked up cleaning fluid to other locations. Ofcourse, other smearing elements or spreader brushes such as flexiblecompliant blade member a sponge elements or a rolling member in contactwith the cleaning surface are also usable. In the case where evenlyspaced multiple spray jets or nozzles direct fluid (spraying, dripping,or flowing) in a regularly spaced pattern without a smearing brush, theevenly spaced multiple spray jets function as a “spreader.”

The scrubbing module 600 may include a scrubbing element, scrub brush,wiper, or wipe cloth e.g. 604; however, the present invention may beused without a scrubbing element. The scrubbing element contacts thecleaning surface during cleaning operations and agitates the cleaningfluid to mix it with contaminants to emulsify, dissolve or otherwisechemically react with contaminants. The scrubbing element, scrub brush,wiper, or wipe cloth also generates a shearing force as it moves withrespect to the cleaning surface and the force helps to break adhesionand other bonds between contaminants and the cleaning surface. Inaddition, the scrubbing element may be passive element or an active andmay contact the cleaning surface directly, may not contact the cleaningsurface at all or may be configured to be movable into and out ofcontact with the cleaning surface.

In one embodiment according to the present invention, a passivescrubbing element, scrub brush, wiper, or wipe cloth is attached to thescrubbing module 600 or other attaching point on the chassis 200 anddisposed to contact the cleaning surface across the cleaning width. Aforce is generated between the passive scrubbing element and thecleaning surface as the robot is transported in the forward direction.The passive scrubbing element, scrub brush, wiper, or wipe cloth maycomprise a plurality of scrubbing bristles held in contact with thecleaning surface, a woven or nonwoven material, e.g. a scrubbing pad orsheet material held in contact with the cleaning surface, or a compliantsolid element such as a sponge or other compliant porous solid foamelement held in contact with the cleaning surface. In particular, aconventional scrubbing brush, sponge, or scrubbing pad used forscrubbing may be fixedly attached to the robot 100 and held in contactwith the cleaning surface across the cleaning width aft of the liquidapplicator to scrub the cleaning surface as the robot 100 advances overthe cleaning surface. In addition, the passive scrubbing element may beconfigured to be replaceable by a user or to be automaticallyreplenished, e.g. using a supply roll and a take up roll for advancingclean scrubbing material into contact with the cleaning surface.

In another embodiment according to the present invention, one or moreactive scrubbing elements are movable with respect to the cleaningsurface and with respect to the robot chassis. Movement of the activescrubbing elements increases the work done between scrubbing element,scrub brush, wiper, or wipe cloths and the cleaning surface. Eachmovable scrubbing element is driven for movement with respect to thechassis 200 by a drive module, also attached to the chassis 200. Activescrubbing elements may also comprise a scrubbing pad or sheet materialheld in contact with the cleaning surface, or a compliant solid elementsuch as a sponge or other compliant porous solid foam element held incontact with the cleaning surface and vibrated by a vibrating backingelement. Other active scrubbing elements may also include a plurality ofscrubbing bristles, and or any movably supported conventional scrubbingbrush, sponge, or scrubbing pad used for scrubbing or an ultra soundemitter may also be used to generate scrubbing action. The relativemotion between active scrubbing elements and the chassis may compriselinear and or rotary motion and the active scrubbing elements may beconfigured to be replaceable or cleanable by a user.

Referring now to FIGS. 10-12 a preferred embodiment of present inventionincludes an active scrubbing element. The active scrubbing elementcomprises a rotatable brush assembly 604 disposed across the cleaningwidth, aft of the liquid applicator nozzles 712, 714, for activelyscrubbing the cleaning surface after the cleaning fluid has been appliedthereon. The rotatable brush assembly 604 comprises a cylindricalbristle holder element 618 for supporting scrubbing bristles 616extending radially outward there from. The rotatable brush assembly 604is supported for rotation about a rotation axis that extendssubstantially parallel with the cleaning width. The scrubbing bristles616 are long enough to interfere with the cleaning surface duringrotation such that the scrubbing bristles 616 are bent by the contactwith the cleaning surface.

Scrubbing bristles 616 are installed in the brush assembly in groups orclumps with each clump comprising a plurality of bristles held by asingle attaching device or holder. Clumps locations are disposed along alongitudinal length of the bristle holder element 618 in a pattern. Thepattern places at least one bristle clump in contact with cleaningsurface across the cleaning width during each revolution of therotatable brush element 604. The rotation of the brush element 604 isclockwise as viewed from the right side such that relative motionbetween the scrubbing bristles 616 and the cleaning surface tends toflick loose contaminants and waste liquid in the aft direction. Inaddition, the friction force generated by clockwise rotation of thebrush element 604 tends drive the robot in the forward direction therebyadding to the forward driving force of the robot transport drive system.The nominal dimension of each scrubbing bristles 616 extended from thecylindrical holder 618 causes the bristle to interfere with the cleaningsurface and there for bend as it makes contact with the surface. Theinterference dimension is the length of bristle that is in excess of thelength required to make contact with the cleaning surface. Each of thesedimensions plus the nominal diameter of the scrubbing bristles 616 maybe varied to affect bristle stiffness and therefore the resultingscrubbing action. Applicants have found that configuring the scrubbingbrush element 604 with nylon bristles having a bend dimension ofapproximately 16-40 mm (0.62-1.6 inches) a bristle diameter ofapproximately 0.15 mm (0.006 inches) and an interference dimension ofapproximately 0.75 mm (0.03 inches) provides good scrubbing performance.In another example, stripes of scrubbing material may be disposed alonga longitudinal length of the bristle holder element 618 in a patternattached thereto for rotation therewith. FIG. 23 depicts a secondschematic exploded isometric view of a cleaning head or scrubbing modulesimilar to that depicted in FIGS. 10 and 11. In FIG. 23, the arrangementof top cover 638, static brush 614, cartridge body 634, squeegee 630,and spreader brush 604 may be more clearly seen. The top cover 638 andcartridge body 634 are pivotally joined by the metal rod 640; thedouble-helix brush 604 rests in the cartridge body 634, yet isremovable, and the squeegee 630 depicted in FIG. 23 is a one-piecesqueegee with channels therethrough for the vacuum to draw fluid.

Squeegee and Wet Vacuum Detail

The scrubbing module 600 may also include a second collecting apparatus(also and alternatively, “wet vacuum”) configured to collect wasteliquid from the cleaning surface across the cleaning width. The secondcollecting apparatus is generally positioned aft of the liquidapplicator nozzles 712, 714, aft of the smearing brush, and aft of thescrubbing element. In a preferred embodiment according to the presentinvention, a scrubbing module 600 is shown in section view in FIG. 12A.The smearing element 612 is shown attached to the scrubbing module atits forward edge and the rotatable scrubbing brush assembly 604 is shownmounted in the center of the scrubbing module. Aft of the scrubbingbrush assembly 604, a squeegee 630 contacts the cleaning surface acrossits entire cleaning width to collect waste liquid as the robot 100advances in the forward direction. A vacuum system draws air in throughports in the squeegee to suction waste liquid up from the cleaningsurface. The vacuum system deposits the waste liquid into a wastestorage container carried on the robot chassis 200. The robot mayalternatively recirculate all or part of the fluid, i.e., a portion ofthe waste fluid may be scavenged, or the waste fluid may be returned toa single, clean/waste tank, either filtered or unfiltered.

As detailed in the section view of FIG. 12A, the squeegee 630 comprisesa vertical element 1002 and a horizontal element 1004. Each of theelements 1002 and 1004 are formed from a substantially flexible andcompliant material such as neoprene or other sponge rubber, silicone orthe like. A single piece squeegee construction is also usable. In apreferred embodiment, the vertical element 1002 comprises a moreflexible durometer material and is more bendable and compliant than thehorizontal element 1004. The vertical squeegee element 1002 contacts thecleaning surface at a lower edge 1006 or along a forward facing surfaceof the vertical element 1002 when the vertical element is slightly benttoward the rear by interference with the cleaning surface. The loweredge 1006 or forward surface remains in contact with the cleaningsurface during robot forward motion and collects waste liquid along theforward surface. The waste liquid pools up along the entire length ofthe forward surface and lower edge 1006. The horizontal squeegee element1004 includes spacer elements 1008 extending rear ward form its mainbody 1010 and the spacer elements 1008 defined a suction channel 1012between the vertical squeegee element 1002 and the horizontal squeegeeelement 1004. The spacer elements 1008 are discrete elements disposedalong the entire cleaning width with open space between adjacent spacerelements 1008 providing a passage for waste liquid to be suctionedthrough.

A vacuum interface port 1014 is provided in the top wall of the scrubbermodule 600. The vacuum port 1014 communicates with the robot air movingsystem and withdraws air through the vacuum port 1014. The scrubbermodule 600 is configured with a sealed vacuum chamber 1016, whichextends from the vacuum port 1014 to the suction channel 1012 andextends along the entire cleaning width. Air drawn from the vacuumchamber 1016 reduces the air pressure at the outlet of the suctionchannel 1012 and the reduced air pressures draws in waste liquid and airfrom the cleaning surface. The waste liquid drawing in through thesuction channel 1012 enters the chamber 1016 and is suctioned out of thechamber 1016 and eventually deposited into a waste material container bythe robot air moving system. Each of the horizontal squeegee element1010 and the vertical squeegee element 1002 form walls of the vacuumchamber 1016 and the squeegee interfaces with the surrounding scrubbingmodule elements are configured to pressure seal the chamber 1016. Inaddition, the spacers 1008 are formed with sufficient stiffness toprevent the suction channel 1012 from closing.

The squeegee vertical element 1002 includes a flexure loop 1018 formedat its mid point. The flexure loop 1018 provides a pivot axis aboutwhich the lower end of the squeegee vertical element can pivot when thesqueegee lower edge 1006 encounters a bump or other discontinuity in thecleaning surface. This also allows the edge 1006 to flex as the robotchanges travel direction. When the squeegee lower edge 1006 is free ofthe bump or discontinuity it returns to its normal operating position.The waste liquid is further suctioned into the waste liquid storagecontainer, compartment, or tank as described below with respect to FIG.10.

In an alternative shown in FIG. 12B, the second collecting apparatuscomprises a squeegee 630 interconnected with a vacuum system. Thesqueegee 630 collects waste liquid in a liquid collection volume 676formed between a longitudinal edge of the squeegee and the cleaningsurface as the robot 100 advances in the forward direction. The vacuumsystem interfaces with the liquid collection volume to suction the wasteliquid up from the cleaning surface and deposit the waste liquid in awaste storage tank carried on the robot chassis 200. The squeegee 630 isshown in FIG. 10 and in section view in FIG. 12B.

As shown in FIG. 12B, the squeegee 630 comprises a substantiallyflexible and compliant element molded from a neoprene rubber, siliconerubber, or the like, attached to the aft end of the scrubbing module 600and disposed across the cleaning width. The squeegee extends downwardfrom the chassis 200 to make contact or near contact with the cleaningsurface. In particular, the squeegee 630 attaches to the aft edge of thescrubber module 600 at a scrubber module lower housing element 634 andextends downwardly to contact or nearly contact the cleaning surface. Asshown in FIG. 12B, the squeegee 630 includes a substantially horizontallower section 652 that extends aft of and downwardly from the lowerhousing element 634 toward the cleaning surface. A forward edge of thesqueegee horizontal lower section 652 includes a plurality of throughholes 654, uniformly disposed across the cleaning width. Each of theplurality of through holes 654 interfaces with a corresponding mountingfinger 656 formed on the lower housing element 634. The interlacedthrough holes 652 and mounting fingers 654 locate the forward edge ofthe squeegee 630 with respect to the lower housing 634 and an adhesivelayer applied between the interlaced elements fluid seals the squeegeelower housing interface at the forward edge.

The squeegee 630 in FIG. 12B is further configured with an aft section658 that attaches to an aft edge of the lower housing element 634 alongthe cleaning width. A plurality of aft extending mounting fingers 660are formed on the lower housing element 634 to receive correspondingthrough holes formed on the squeegee aft section 658. The interlacedthrough holes 662 and aft mounting fingers 660 locate the squeegee aftsection 658 with respect to the lower housing 634 and an adhesive layerapplied between the interlaced elements fluid seals the squeegee lowerhousing interface at the aft edge. Of course, any attaching means can beemployed.

As further shown in FIG. 12B, a vacuum chamber 664 is formed by surfacesof the squeegee lower section 652, the squeegee aft section 658 andsurfaces of the lower housing element 634. The vacuum chamber 664extends longitudinally along the squeegee and lower housing interfaceacross the cleaning width and is fluidly connected with a waste liquidstorage tank carried by the chassis by one or more fluid conduits 666,described below. In a preferred embodiment of FIG. 12B, two fluidconduits 666 interface with the vacuum chamber 664 at distal endsthereof. Each of the fluid conduits 666 couple to the vacuum chamber 664via an elastomeric sealing gasket 670. The gasket 670 installs in anaperture of the lower housing 634 and is held therein by an adhesivebond, interference fit or other appropriate holding means. The gasket670 includes an aperture passing therethrough and is sized to receivethe fluid conduit 666 therein. The outside wall of the conduit 666 istapered to provide a lead in to the gasket 670. The conduit 666 isintegral with the waste liquid storage container and makes a liquid gastight seal with the gasket 670 when fully inserted therein.

The squeegee of FIG. 12B includes a longitudinal ridge 672 formed at aninterface between the horizontal lower section 652 and the aft section658 across the cleaning width. The ridge 672 is supported in contactwith, or nearly in contact with, the cleaning surface during normaloperation. Forward of the ridge 672 the horizontal lower section 652 iscontoured to provide the waste liquid collecting volume 674. A pluralityof suction ports 668 extend from the liquid collecting volume 674,through the squeegee horizontal lower section 652 and into the vacuumchamber 664. When negative air pressure is generated within the vacuumchamber 664, waste liquid is drawn up from the liquid collecting volume674 into the vacuum chamber 664. The waste liquid is further suctionedinto the waste liquid storage container or tank as described below.

A third squeegee configuration is shown in FIGS. 42 through 45. FIG. 42depicts a side schematic view; FIG. 43 depicts a perspective view, FIG.44 depicts another side schematic view, and FIG. 45 depicts a third sideschematic view. This squeegee is a split squeegee, where a frontcrenellated panel provides separation to create vacuum channels, and arear squeegee wiper maintains ground contact and collects fluid for thevacuum. These members are placed on different parts of the cleaninghead, and match up when the cleaning head is closed.

As shown in FIG. 42, the cartridge housing or shroud opens about a hingepoint 613 (to the right, above the static brush 612). The static brush612 (e.g., the spreader brush) is mounted in the lower part of theshroud. The spinning brush 604 (e.g., the powered brush or wiper) issupported by the lower part of the shroud as well. The front squeegee1004 is attached to the shroud bottom. As shown in FIG. 42, the frontsqueegee 1004 is shown in a position that it would take if it did notcontact the rear shroud, i.e., the front squeegee 1004 is eitherresilient or biased toward the rear squeegee 1006, which is, in thiscase, a resilient elastomer. When the rear squeegee 1006, which can beover-molded to the shroud top, is closed with the shroud top or cover,the two squeegees settle into the operating position (shown in sectionin FIG. 44). The rear squeegee 1006, which is resilient, is moved towardthe rear, and the front squeegee 1004 is just slightly moved toward thefront, sliding slightly along the rear squeegee 1006. The settledposition is slightly angled and provides the vacuum channels at justabove the floor surface, with sufficient floor contact of the rearsqueegee 1006. As shown in FIG. 43, the front squeegee 1004 is formed asa crenellated panel angled from the vertical and extending along theworking width, the crenellated panel leading up to a flexure corner 1009pointing upwards that also extends along the working width, which turnsthe corner, then curves downward and forward and leads into a horizontalpanel for mounting. The crenellations or ribs 1008, visible in FIG. 43,maintain a correct flow path between the leading squeegee 1004 and thetrailing squeegee 1006. The flexure angle provides a good range ofmotion and flexibility, from both fore and aft for the two squeegeesworking together (as discussed herein, able to overcome obstacles theheight of the robot ground clearance).

The rear squeegee 1006, shown in section in FIG. 45, is about 1 mm thick(with other dimensions as discussed herein) and includes a flat panelarranged vertically and extending along the working width, a compliantelement as a reverse C-curve flexure loop 1018, thinner than the flatpanel and also extending along the working width, and a snap retentionfeature 1019 (shown retained in FIG. 44). In the operating position, therear squeegee 1006 bends generally between the snap retention element1019 and the flat panel 1006, with much of the bending taking placealong the height of the C-curve flexure loop 1018. Other structures,such as hinges or different materials, can be used as the compliantelement and are considered to fall within this language. The rearsqueegee 1006 can be formed, as shown in FIG. 42, to extend all the wayto the top and over within the vacuum chamber. If through-holes areformed or made in the top rear squeegee material, the entire rearsqueegee can act as both a squeegee and as a seal for the wet vacuumports at the top of the wet vacuum chamber 1016, as the resilient rearsqueegee material closely meets the vacuum ducting as the cleaning headcartridge is matched to the robot. In other circumstances, where therear squeegee 1006 is formed from a different material than all or someof the upper portion of the rear squeegee 1006, or where the rearsqueegee 1006 does not extend all the way to the top or around thevacuum chamber, alternative seals may be provided.

FIG. 44 in general shows the operating position, wherein the rearsqueegee 1006 angles back, and both flexure portions are positioned topermit flexure of the squeegee combination. Although the rear squeegee1006 is formed as a flat panel wall (and alternatives as discussedherein) with a planar bottom, in the operating position as it is angledback by the front squeegee 1004, and a working edge, the edge of thewall and wall bottom, contacts the ground rather than the planar bottom.The contact force, area, angle, flatness and edge profile of thiscontact is a large contributor to the drag of the cleaning elements, andas discussed herein, is to be maintained at a sufficiently low level ofdrag to permit traction while still enabling the squeegeeing of water onflat or irregular surfaces.

One squeegee as described is split fore/aft for easy disassembly andcleaning. This allows the user easily to remove the front and rearsections of the squeegee and associated vacuum chamber, allows for easyremoval of any blockage or obstruction such as will from time to time befound in the vacuum path. It also allows the user to place the cleaninghead in, for example, a dishwasher to more thoroughly clean and sanitizeit. However, the squeegee may be alternatively split left/right as well.as the robot spins in place or turns, the squeegee can assume aconfiguration in which one side is bent backward and one side is bentforward. The point at which the bend switches from backward to forwardcan act as a more or less solid column under the robot, tending to highcenter it and interfere with mobility. By providing a split in thecenter of the squeegee, this tendency can be mitigated or eliminated,increasing mobility.

Referring to FIG. 10, the scrubbing module 600 is formed as a separatesubsystem that is removable from the robot chassis. The scrubbing module600 includes support elements comprising a molded two-part housingformed by the lower housing element 634 and a mating upper housingelement 636. The lower and upper housing elements are formed to housethe rotatable scrubbing brush assembly 604 therein and to support it forrotation with respect to the chassis. The lower and upper housingelements 634 and 636 are attached together at a forward edge thereof bya hinged attaching arrangement. Each housing element 634 and 636includes a plurality of interlacing hinge elements 638 for receiving ahinge rod 640 therein to form the hinged connection. Of course, otherhinging arrangements can be used. The lower and upper housing elements634 and 636 form a longitudinal cavity for capturing the rotatablescrubbing brush assembly 604 therein and may be opened by a user whenthe scrubbing module 600 is removed from the robot 100. The user maythen remove the rotatable scrubbing brush assembly 604 from the housingto clean it replace it or to clear a jam.

The rotatable scrubbing brush assembly 604 comprises the cylindricalbristle holder 618, which may be formed as a solid element such as asold shaft formed of glass-filled ABS plastic or glass-filled nylon.Alternately the bristle holder 618 may comprise a molded shaft with acore support shaft 642 inserted through a longitudinal bore formedthrough the molded shaft. The core support shaft 642 may be installed bya press fit or other appropriate attaching means for fixedly attachingthe bristle holder 618 and the core support shaft 642 together. The coresupport shaft 642 is provided to stiffen the brush assembly 604 and istherefore formed from a stiff material such as a stainless steel rodwith a diameter of approximately 10-15 mm (0.4-0.6 inches). The coresupport shaft 642 is formed with sufficient stiffness to preventexcessive bending of the cylindrical brush holder. In addition, the coresupport shaft 642 may be configured to resist corrosion and or abrasionduring normal use.

As noted herein a powered brush is employed. The brush itself is easilyremovable from the cleaning head. This allows for the possibility forswapping in different brushes for special situations without replacingthe entire cleaning head. The invention contemplates a set of brushes,each having differing physical structure (e.g., tight bristle spacing,loose, stiff bristle, wipers and bristles, etc.) for wood flooring,grout lines, uneven floors, etc. Different bristle compositions andconfigurations may be appropriate for different floor surfaces. Eachtuft of bristles can be composed of a different number and type ofbristles. The size of the tuft and the composition of the bristlesimpact its cleaning ability, energy consumption, and ability to handledifferent floor textures, and fluid management. Setting tufts at alateral angle—allows cleaning beyond the edge of the brush core, andsetting tufts at a tangential angle allows bristle tips to moreaggressively strike the floor and reach deeper into cracks/grout lines.

The bristle holder 618 is configured with a plurality of bristlereceiving holes 620 bored or otherwise formed perpendicular with therotation axis of the scrubbing brush assembly 604. Bristle receivingholes 620 are filled with clumps of scrubbing bristles 616 which arebonded or otherwise held therein. In one example embodiment, two spiralpatterns of receiving holes 620 are populated with bristles 616. A firstspiral pattern has a first clump 622 and a second clump 624 andsubsequent bristle clumps follow a spiral path pattern 626 around theholder outside diameter. A second spiral pattern 628 starts with a firstclump 630 substantially diametrically opposed to the clump 622. Eachpattern of bristle clumps is offset along the bristle holderlongitudinal axis to contact different points across the cleaning width.However, the patterns are arranged to scrub the entire cleaning widthwith each full rotation of the bristle holder 618. In addition, thepattern is arranged to fully contact only a small number of bristleclumps with cleaning surface simultaneously, (e.g., two) in order toreduce the bending force exerted upon and the torque required to rotatethe scrubbing brush assembly 604. Of course, other scrubbing brushconfigurations having different bristle patterns, materials andinsertion angles are usable. In particular, bristles at the right edgeof the scrubbing element may be inserted at an angle and made longer toextend the cleaning action of the scrubbing brush further toward theright edge of the robot for cleaning near the edge of a wall.

The scrubbing brush assembly 604 couples with a scrubbing brush rotarydrive module 606 which is shown schematically in FIG. 13. The scrubbingbrush rotary drive module 606 includes a DC brush rotary drive motor608, which is driven at a constant angular velocity by a motor driver650. The motor driver 650 is set to drive the motor 608 at a voltage andDC current level that provides the desired angular velocity of therotary brush assembly 604, which in one embodiment is about 1500 RPM;values as low as about 500 RPM, and as high as about 3000 RPM arecontemplated. The drive motor 608 is coupled to a mechanical drivetransmission 610 that increases the drive torque and transfers therotary drive axis from the drive motor 608, which is positioned on thetop side of the chassis 200, to the rotation axis of the scrubbing brushassembly 604, which is positioned on a bottom side of the chassis 200. Adrive coupling 642 extends from the mechanical drive transmission 610and mates with the rotatable scrubbing brush assembly 604 at its leftend. The action of sliding the scrubber module 600 into the cavity 602couples the left end of the rotatable brush assembly 604 with the drivecoupling 642. Coupling of the rotatable brush assembly 604 aligns itsleft end with a desired rotation axis, supports the left end forrotation, and delivers a rotary drive force to the left end. The rightend of the brush assembly 604 includes a bushing or other rotationalsupport element 643 for interfacing with bearing surfaces provided onthe module housing elements 634, 636.

The scrubber module 600 further includes a molded right end element 644,which encloses the right end of the module to prevent debris and sprayfrom escaping the module. The right end element 644 is finished on itsexternal surfaces to integrate with the style and form of adjacentexternal surfaces of the robot 100. The lower housing element 634 isconfigured to provide attaching features for attaching the smearingbrush 612 to its forward edge and for attaching the squeegee 630 to itsaft edge. A pivotal latching element 646 is shown in FIG. 10 and is usedto latch the scrubber module 600 in its operating position when it iscorrectly installed in the cavity 632. The latch 646 attaches toattaching features provided on the top side of the chassis 200 and isbiased into a closed position by a torsion spring 648. A latching claw649 passes through the chassis 200 and latches onto a hook elementformed on the upper housing 636. The structural elements of the wetcleaning module 600 may be molded from a suitable plastic material suchas a polycarbonate, ABS, or other materials or combinations ofmaterials. In particular, these include the lower housing 634, the upperhousing 636, the right end element 644, and the latch 646.

Air Moving Subsystems or Vacuum & Blower Assembly

FIG. 14 depicts a schematic representation of a wet dry vacuum module500 and its interface with the cleaning elements of the robot 100. Thewet dry vacuum module 500 interfaces with the first collecting apparatusto suction up loose particulates from the cleaning surface and with thesecond collecting apparatus to suction up waste liquid from the cleaningsurface. The wet dry vacuum module 500 also interfaces with anintegrated liquid storage container 800 attached to the chassis 200 anddeposits loose particulates and waste liquid into one or more wastecontainers housed therein.

Referring to FIGS. 14 and 15, the wet dry vacuum module 500 comprises asingle fan assembly 502; however, two or more fans can be used withoutdeviating from the present invention. The fan assembly 502 includes arotary fan motor 504, having a fixed housing 506 and a rotating shaft508 extending therefrom. The fixed motor housing 506 attaches to the fanassembly 502 at an external surface of a rear shroud 510 by threadedfasteners, or the like. The motor shaft 508 extends through the rearshroud 510 and a fan impeller 512 is attached to the motor shaft 508 bya press fit, or by another appropriate attaching means, for causing theimpeller 512 to rotate with the motor shaft 508. A front shroud 514couples with the rear shroud 510 for housing the fan impeller 512 in ahollow cavity formed between the front and rear shrouds. The fan frontshroud 514 includes a circular air intake port 516 formed integraltherewith and positioned substantially coaxial with a rotation axis ofthe motor shaft 508 and impeller 512. The front and rear shrouds 510,514 together form an air exit port 518 at a distal radial edge of thefan assembly 502.

The fan impeller 512 generally comprises a plurality of blade elementsarranged about a central rotation axis thereof and is configured to drawair axially inward along its rotation axis and expel the air radiallyoutward when the impeller 718 is rotated. Rotation of the impeller 512creates a negative air pressure zone, or vacuum, on its input side and apositive air pressure zone at its output side. The fan motor 710 isconfigured to rotate the impeller 715 at a substantially constant rateof rotational velocity, e.g. 14,000 RPM, which generates a higher airflow rate than conventional fans for vacuum cleaners or wet vacuums.Rates as low as about 1,000 RPM and as high as about 25,000 RPM arecontemplated, depending on configuration of the fan. A flywheel may beconcentric with the fan impeller 715, especially if the fan is locatedclose to the center of gravity of the robot.

The air flow rate of the fan may range from about 60-100 CFM in free airand about 60 CFM in the robot, with approximately 60% of this flow rateis dedicated to the wet vac portion of the robot. This percentage isadjustable, either manually by the user or during manufacture.Adjustment of the airflow between the wet and dry vac systems wouldallow the user to configure the user to address particular needs ofcertain applications. Additionally, a multi-stage fan design couldproduce a similar air flow rate, but higher static pressure andvelocity, which helps to maintain flow. Higher velocity also enables thedevice to entrain dry particles and lift and pull fluids. The multipleribs and channels of the squeegee help to create areas of localized highvelocity for entraining particles. In one embodiment, total crosssectional area is 180 square mm for each of the wet and dry vacuum(squeegee and suction port).

As shown in FIGS. 24 and 25, one example of an impeller 512 is a twostage fan assembled from a base plate 512 a having a hub or nose formedtherein, and a vane assembly 512 b, having an inducer 512 c and exducer512 d formed therein. As shown in FIG. 24, the inducer 512 c includesforward curved inlet blades, which increase flow rate and efficiencyover fan designs that do not use an inducer. The exducer blades are backswept and contribute to centrifugal flow. Also, as shown in FIG. 24,specifically sized balancing pins 512 e are positioned at regulardegreed intervals about the rim of the vane assembly 512 b. The pins areused to assist material removal for balancing as a fan assembly designedfor sustained 14,000 RPM operation of a plastic fan. Both the base plate512 b and vane assembly 512 b are formed from resin or plastic, and havevarious irregularities and density variations. After the base plate 512b and vane assembly 512 b are assembled, a balancing machine is used toidentify a number of pins at specific positions to remove in order tobalance the impeller. As shown in FIGS. 15 and 26, the impeller 512 isarranged within a scroll formed from the front and rear shrouds 512,514. The scroll is for static pressure recovery and flow collection foruse in the “blow” portion of the dry vacuum system. As shown in FIG. 26,a front scroll 514 and a rear scroll 510 are assembled together to holdthe impeller 512, a seal 516 sealing the inducer end of the impeller512. The impeller 512 provides vacuum for the wet and dry vacuumsections, and a part of the output is split off to provide an air jet tothe dry vacuum section. A bifurcator 515 splits a smaller portion of theoutput air flow off using a rear duct 517 b, while most of the outputair flow is exhausted via an exhaust duct and muffler. As shown in FIG.26, a circuit board 504 a for the fan motor 504 is placed near the fanmotor. This circuit board is one that may be rendered water resistant orwaterproofed by the structures discussed herein.

With respect to the blower shown in FIGS. 24-26, the scroll design foldsback in on itself to allow a 30 percent larger impeller, without anyloss in scroll volume while maintaining the same package size. Theinducer is the portion of the fan blade dedicated to inlet flow only.Alternatively or in addition, a passive or active bypass system (e.g., agovernor plus vane; or a motorized actuator plus a vane) may be providedto balance the blower outlet to suction port inlet flows for optimumperformance over a variety of system conditions. A “moat” (i.e., achannel or wall) is alternatively or addition, in front of impeller toprevent water from entering impeller. The impeller used for air handlingmoves air through the system at considerable velocity, which can lead towater being pulled out of the dirty tank, through the impeller, and backto the floor. The moat is designed to prevent or limit this occurrence.

As shown in the FIGS., the main exhaust is in line with the cleaninghead. In other words, while the cleaning head extends to the edge of thedominant side of the robot, a space of up to ⅕ of the robot is preservedbeside the cleaning head on the robot diameter. As noted above, the geartrain and/or motor for the cleaning head powered brush or wiper may beplaced in this space. Additionally, the main exhaust may be placed inthis space. Placing the main exhaust, which is quite strong (being mostof the exhaust for the wet and dry vacuums, only a part used to blowdebris in the dry vacuum) along the line of the cleaning head preventsapplied, brushed, and/or wiped fluid from escaping the perimeter of therobot on the non-dominant side. Additionally, it is a feature of thecleaning head that the cartridge housing is internally dry (notconnected to any fluid generating devices, and generally sealed againstwetness), such that upon removal of the cleaning head cartridge, theuser is presented with dry surfaces for handling the cleaning head. Theexhaust also may be placed behind the cleaning head to assist in drying.In such a case, the exhaust could be spread by appropriate ducts andchannels.

As shown schematically in FIG. 14, a closed air duct or conduit 552 isconnected between the fan housing exit port 518 and the air jet port 554of the first cleaning zone A and delivers high pressure air to the airjet port 554. At the opposite end of the first cleaning zone A, a closedair duct or conduit 558 connects the air intake port 556 with theintegrated liquid storage container module 800 at a container intakeaperture 557. Integral with the integrated storage container or tank800, a conduit 832, detailed below, connects the container intakeaperture 557 with a plenum 562. The plenum 562 comprises a union forreceiving a plurality of air ducts connected thereto. The plenum 562 isdisposed above a waste storage container portion of the integratedliquid storage container or tank module 800. The plenum 562 and wastecontainer portion are configured to deposit loose particulates suctionedup from the cleaning surface by the air intake port 556 into the wastecontainer. The plenum 652 is in fluid communication with the fan intakeport 516 via a closed air duct or conduit comprising a conduit 564, notshown, connected between the fan assembly and a container air exitaperture 566. The container air exit aperture 566 is fluidly connectedwith the plenum 562 by an air conduit 830 that is incorporated withinthe integrated liquid storage tank module 800. Rotation of the fanimpeller 512 generates a negative air pressure or vacuum inside theplenum 560. The negative air pressure generated within the plenum 560draws air and loose particulates in from the air intake port 556.

As further shown schematically in FIG. 14, a pair of closed air ducts orconduits 666 interface with scrubbing module 600 of the second cleaningzone B. The air conduits 666, shown in section view in FIG. 10 compriseexternal tubes extending downwardly from the integrated liquid containermodule 800. The external tubes 666 insert into the scrubber module upperhousing gaskets 670.

As shown in FIG. 14, conduits 834 and 836 fluidly connect each externaltube 666 to the plenum 652. Negative air pressure generated within theplenum 652 draws air from the vacuum chamber 664 via the conduits 834,836 and 666 to suction waste liquid from the cleaning surface via thesuction ports 668 passing from the vacuum chamber 664 to the wasteliquid collecting volume 674. The waste liquid is draw into the plenum562 and deposited into the waste liquid storage container.

Of course other wet dry vacuum configurations are contemplated withoutdeviating from the present invention. In one example, a first fanassembly may be configured to collect loose particulates from the firstcleaning zone and deposit the loose particulates in the first wastestorage container or tank and a second fan assembly may be configured tocollect waste liquid from the second cleaning zone and deposit the wasteliquid into a second waste storage container or tank. Integrated LiquidStorage Tank

Elements of the integrated liquid storage container module 800 are shownin FIGS. 1, 12, 14, 16 and 17. Referring to FIG. 16, the integratedliquid storage container 800 is formed with at least two liquid storagecontainer or tank portions. One container portion comprises a wastecontainer portion and the second container portion comprises a cleaningfluid storage container or tank portion. In another embodiment of thepresent invention the two storage containers are formed as an integralunit that is configured to attach to the chassis 200 and to be removablefrom the chassis by a user to empty the waste container portion and tofill the cleaning fluid container portion. In an alternate embodiment,the integrated storage containers can be filled and emptied autonomouslywhen the robot 100 is docked with a bas station configured fortransferring cleaning fluid and waste material to and from the robot100. The cleaning fluid container portion S comprises a sealed supplytank for holding a supply of the cleaning fluid. The waste containerportion W comprises a sealed waste tank for storing loose particulatescollected by the first collecting apparatus and for storing waste liquidcollected by the second collecting apparatus.

The waste tank D (or compartment D) comprises a first molded plasticelement formed with a base surface 804 and an integrally formedperimeter wall 806 disposed generally orthogonal from the base surface804. The base surface 804 is formed with various contours to conform tothe space available on the chassis 200 and to provide a detent area 164that is used to orient the integrated liquid storage container or tankmodule 800 on the chassis 200. The detent 164 includes a pair ofchannels 808 that interface with corresponding alignment rails 208formed on a hinge element 202, attached to the chassis 200 and describedbelow. The perimeter wall 806 includes finished external surfaces 810that are colored and formed in accordance with the style and form ofother external robot surfaces. The waste tank D may also include a tanklevel sensor housed therein and be configured to communicate a tanklevel signal to the master controller 300 when the waste tank D (orcompartment D) is full. The level sensor may comprise a pair ofconductive electrodes disposed inside the tank and separated from eachother. A measurement circuit applies an electrical potential differencebetween the electrodes from outside the tank. When the tank is empty nocurrent flow between the electrodes. However, when both electrodes aresubmerged in waste liquid, current flows through the waste liquid fromone electrode to the other. Accordingly, the electrodes may be locatedat positions with the tank for sensing the level of fluid within thetank.

The cleaning fluid storage container or tank S is formed in part by asecond molded plastic element 812. The second molded element 812 isgenerally circular in cross-section and formed with a substantiallyuniform thickness between opposing top and bottom surfaces. The element812 mates with the waste container perimeter wall 810 and is bonded orotherwise attached thereto to seal the waste container, compartment, ortank D. The plenum 562 is incorporated into the second molded element812 and positioned vertically above the waste container, tank D (orcompartment D) when the cleaning robot is operating. The plenum 562 mayalso comprise a separate molded element.

The second molded element 812 is contoured to provide a second containerportion for holding a supply of cleaning fluid. The second containerportion is formed in part by a downwardly sloping forward section havingan integrally formed first perimeter wall 816 disposed in a generallyvertically upward direction. The first perimeter wall 816 forms a firstportion of an enclosing perimeter wall of the liquid storage containerS. The molded element 812 is further contoured to conform to the spaceavailable on the chassis 200. The molded element 812 also includes thecontainer air input aperture 840, for interfacing with first cleaningzone air conduit 558. The molded element 812 also includes the containerair exit aperture 838, for interfacing with the fan assembly 502 via theconduit 564.

A molded cover assembly 818 attaches to the molded element 812. Thecover assembly 818 includes a second portion of the supply tankperimeter wall formed thereon and provides a top wall 824 of the supplytank enclosure. The cover assembly 818 attaches to the first perimeterwall portion 816 and to other surfaces of the molded element 814 and isbonded or otherwise attached thereto to seal the supply container S. Thesupply container S may include a tank empty sensor housed therein and beconfigured to communicate a tank empty signal to the master controller300 when the upper tank is empty.

The cover assembly 818 comprises a molded plastic cover element havingfinished external surfaces 820, 822 and 824. The finished externalsurfaces are finished in accordance with the style and form of otherexternal robot surfaces and may therefore be colored and or styledappropriately. The cover assembly 818 includes user access ports 166,168 to the waste container tank D to the supply container S,respectively. The cover assembly 818 also includes the handle 162 and ahandle pivot element 163 attached thereto and operable to unlatch theintegrated liquid storage tank 800 from the chassis 200 or to pick upthe entire robot 100.

According to the invention, the plenum 562 and each of the air conduits830, 832, 834 and 836 are inside the cleaning fluid supply container Sand the interconnections of each of these elements are liquid and gassealed to prevent cleaning fluid and waste materials from being mixedtogether. The plenum 562 is formed vertically above the waste container,compartment, or tank D so that waste liquid waste and loose particulatessuctioned into the plenum 562 will drop into the waste tank D (orcompartment D) under the force of gravity. The plenum side surfaces 828include four apertures formed therethrough for interconnecting theplenum 562 with the four closed air conduits interfaced therewith. Eachof the four closed air conduits 830, 832, 834 and 836 may comprise amolded plastic tube element formed with ends configured to interfacewith an appropriate mating aperture.

As shown in FIG. 16, the container air exit aperture 838 is generallyrectangular and the conduit 830 connecting the container air exitaperture 838 and the plenum 562 is shaped with a generally rectangularend. This configuration provides a large area exit aperture 838 forreceiving an air filter associated therewith. The air filter is attachedto the fan intake conduit 564 to filter air drawn in by the fan assembly502. When the integrated storage tank 800 is removed from the robot, theair filter remains attached to the air conduit 564 and may be cleaned inplace or removed for cleaning or replacement as required. The area ofthe air filter and the container exit aperture 838 are formed largeenough to allow the wet dry vacuum system to operate even when up toabout 50% or more of the air flow through the filter is blocked bydebris trapped therein.

FIG. 27 depicts a second schematic exploded isometric view showingelements of an integrated tank similar to that of FIG. 16. FIG. 27depicts many of the same or similar elements as FIG. 3. Some alternativeterminology is used in the following description. The elements shown inFIG. 27 are the handle, a manifold including plenum 830 and tubes 832,834, 836 (in this embodiment, the plenum and air flow conduits are allintegral; in other embodiments, the air flow conduits would be replacedwith rubber guide tubes), a pump filter, and a magnet reed. FIG. 27shows a D-shaped flexible rubber tank cap for the clean tank, a similarone for the waste tank (these rubber tank caps include an inner circularseal that conforms to the shape of the tubes leading to thecompartments, and a D-shaped outer part that has a matching receiver inthe tank lid, as depicted in FIG. 27). When the tank is loaded in theclevis-like holder or pivot clamp, the holder can assist in holding shutboth of the D-shaped flexible rubber tank caps. The figure also depictsthe tank bottom (which forms the dirty compartment), the tank middle,and the tank top (which forms the clean compartment). As show, theplenum and/or conduits for the dry and/or wet vacuums extend through theclean tank. This would not generally be found in a larger device, as alarger device would have space to arrange vacuum and/or other air flowconduits outside clean or dirty water tanks. Alternatively, only some ofthe conduits for the vacuum could extend through the clean tank (e.g.,the wet only, the dry only, one wet and one dry), or some or all of theconduits could extend through the dirty tank. Alternatively, one or moreconduits could extend through both tanks. Still further alternatively,the conduits could be formed in another layer, i.e., be sandwichedbetween two tank middle plates. FIG. 27 also depicts an O-ring forsealing the tank top to a tube passing from the tank top through thetank middle to the dirty compartment.

FIGS. 28-30 show a sealing flap 598, airfoil, foam/airflow wall, andball 594 within the integrated tank 592. FIG. 31 is an isometric view ofa foam blocking wall within the integrated tank 592.

As shown in FIG. 27, an aperture 562 a at the bottom of the plenum (inthis embodiment, “bottom” refers to the operating orientation) permitsparticulates and waste water to drop into the waste tank D. As shown inFIG. 16A, this aperture is relatively large. When the tank or robot islifted and leaves the operating orientation, collected waste must beretained in the waste tank D to prevent it from entering the fan orescaping the waste tank to wet the user or floor. As shown in FIGS.28-30, a hinged flap 598 is provided to seal the aperture 562 a.

The hinged flap 598 is hinged at one side of the aperture 562 a, andopens down. That is, when the robot operates, the flap 598 is to be keptopen, to permit waste to enter the waste tank D. However, air flowpassing over the flap 598 toward the vacuum side of the fan assembly 502creates a low pressure region above the flap 598 (Venturi/BernoulliEffect), which can tend to pull up and close the flap in some operatingconditions. An airfoil 596 attached to the flap 598 within the plenum562 is introduced into this air flow, and the down-force effect of theairfoil 596 dominates the Bernoulli Effect, keeping the flap 598 openwhenever significant air flow is present. The airfoil 596 is shaped as agenerally horizontal (and, in certain embodiments, upswept) wing 596 amounted atop a vertical fin 596 b, resembling a T assembly airplanetail. The airfoil 596 is swept in a direction to create down-force orflap-opening force during robot operation.

As shown in FIGS. 28-30, the hinged flap 598, however, is allowed toopen no farther than a ball 594. The ball 594 is provided below the flap598 to close the flap 598 when the tank or robot are moved from theoperating orientation to a non-horizontal, vertical or partiallyvertical orientation (e.g., when the tank alone or robot is beingcarried). Alternatively, the ball 594 may prevent the flap 598 frommoving more than a predetermined distance away from the aperture.Regardless of the degree of movement of the flap 598, the arrangement ofthe ball 594 and flap 598 provides for opening and closing the flap 598at appropriate times. A downwardly open upper cone 598 a is formed inthe bottom of the hinged flap, and an upwardly open lower cone 592 isformed in the waste tank D. The walls of each cone are less than 45degrees from horizontal, the walls of the lower cone 592 being shallowerthan those of the upper cone 598 a and less than about 30 degrees fromhorizontal. In a normal operating orientation, the ball 594 rests in thelower cone 592, and waste drops through the aperture 562 a and aroundthe ball 594. When the tank or robot are moved into any orientationother than horizontal, the ball 594 escapes the shallow lower cone 592and travels along the converging walls of the upper and lower cone,pushing on and closing the flap 598. A matching lip seal 562 b-598 aaround the aperture 562 a and flap 598 prevents waste from escaping thewaste tank D when the flap 598 is closed by the ball 594.

The vertical fin 596 b, however, serves a purpose other than merelysupporting the airfoil(s) 596 a. The vertical fin 596 b forms a verticalwall that extends substantially across the length of the flap 598. Thiswall begins at or near the entry of the wet vacuum conduit 832 and dryvacuum conduits 834, 836 into the plenum 562, and separates the dryvacuum air stream(s) from the wet vacuum air stream across the length ofthe flap 598 as noted, as well as substantially across the length of theplenum 562. Accordingly, particulates will generally tend to remain drywhile they drop into the waste tank D. The dry side air flow moves athigher speed than the wet side air flow entering the plenum. Keepingfoam on the low speed side helps the foam move into the tank.

As shown in FIGS. 28-30, the flap-ball-airfoil arrangement uses gravityand existing air flow to open and close the flap/aperture depending oncircumstances, and generally avoids issues of corrosion or collection ofsludge, which could adversely affect more complex actuation. Thecombination constitutes an aperture-closing member (the flap); a memberthat helps open the flap during operation (the airfoil); and a memberthat helps close the flap when the robot is moved to a non-operatingposition (the ball). It may not be necessary to close the flap when therobot is not operating but remains horizontal, as gravity prevents theescape of waste fluid, and there exists some advantage to keeping theflap open to permit fluid in the plenum to drip into the waste tankafter air flow stops. In cases where the flap should be closed duringnon-operation, however, other mechanical means (including airfoils,springs, balls, or weights) could close the flap as soon as air flowstops, e.g., a member that tends to close the flap except duringoperation could also or alternatively be included. Unpowered,non-electrical actuation of such a mechanism would require noindependent power supply, and it is noted that the flap-ball-airfoilcombination is simple, robust, and durable. Regardless, electricaland/or fluid-powered actuators still may be used in lieu of or inaddition to mechanical devices such as airfoils, balls, springs(including elastomers), and weights.

As shown in FIG. 31, one particular alternative technique formaintaining the flap appropriately open or closed would employ apendulum or plumb weight arranged to pull open, or permit to open, theflap during operation and to swing to close the flap when the tank orrobot is moved to a non-horizontal orientation. The pendulum or plumbweight could either hang freely from a position near the flap bottom, orcould be attached to a relatively rigid multi-way arm or “hat” angledfrom the pendulum “shaft,” the pendulum pivoting substantially about theangle, preferably about a multi-way ball, shoulder, or loosely coupledaxis that permits the arms to tilt relative to the flap. One supportthat provides an appropriate axis is a conic shape with a small hole atthe point of the cone, the cone opening down, and the shaft of thependulum being relatively loose in the hole at the point of the cone. Ifthe hat or arms are above the hole, and the weight movable within thecone, the assembly will keep the arms horizontal until the robot or tankis moved away from the horizontal, in which case the pendulum shafttilts inside the hole and cone, at least one part of the hat or armsthen pushing the flap closed. The flap can include a seat for the hat orarms that is internally curved along the hat to permit clearance andfree movement as appropriate. The pendulum weight pivots the arms or hatso that the arms or hat are substantially horizontal when the robot ortank is horizontal (pulling open or permitting the relatively compliantflap to open when the robot or tank is horizontal) and at least one armor part of the hat pushes the flap against the seal when the robot ortank is not horizontal (pushing the relatively compliant flap closed inthe vertical or non-horizontal orientation). The pendulum weight shouldmove freely, and can be positioned as far as possible from the flap(proximate the far walls of the tank) to provide a longer moment arm.

FIG. 32 is an isometric view of a foam blocking wall 580 within theintegrated tank D. As noted herein, a waste fluid (WTF) sensor is usedat the top of the waste fluid tank. The waste fluid sensor isconductive, and when waste fluid reaches the top of the tank, a currentmay pass between two wire probes at the top of the compartment,indicating via a visible or audible signal emitted from the robot thatthe waste compartment is full. During cleaning, however, depending onthe cleaning fluid and what has been cleaned, foam may build up in thewaste fluid compartment and, as foam can conduct a current, give a falsepositive reading on the waste fluid full sensor. The foam tends to begenerated before, or during entry of waste fluid into the aperture orentrance port to the waste compartment. As shown in FIG. 32, a wall isprovided between an isolated section 579 of the waste fluid compartment(in which one or both of the probes are located) and the remainder ofthe tank D. The wall 580 includes a gap or fluid entrance port 578 atthe bottom of the tank D, but otherwise is a complete wall isolating theprobe chamber 579, with sufficient air flow allowed to enable water toeasily enter the chamber, and subsequently rise therein. Foam can existin the main chamber D, but does not transfer to the isolated probechamber 579, which remains generally foam free. Accordingly, the sensordoes not generally register the presence of foam in this configuration.

Returning to FIGS. 16 and 28, each of the container apertures 840 and838 are configured with a gasket, not shown, positioned external to thecontainer aperture. The gaskets provide substantially airtight sealsbetween the container assembly 800 and the conduits 564 and 558. In oneembodiment, the gaskets remain affixed to the chassis 200 when theintegrated liquid supply container 800 is removed from the chassis 200.The seal is formed when the container assembly 800 is latched in placeon the robot chassis. In addition, some of the container apertures mayinclude a flap seal or the like for preventing liquid from exiting thecontainer while it is carried by a user. The flap seal remains attachedto the container.

FIG. 28 shows that the air conduits are connected to the plenum withflexible (e.g., elastomer) tubes. These tubes help account for thestack-up of manufacturing tolerances. Alternatively, as discussedherein, the entire set of plenum and conduits may be formed as an, e.g.,blow-molded or other unit; or the plenum and conduits may be matchingtop and bottom injection or other molded units.

Thus according to the present invention, the fan assembly 502 generatesa negative pressure of vacuum which evacuates air conduit 564, draws airthrough the air filter disposed at the end of air conduit 564, evacuatesthe fan intake conduit 830 and the plenum 562. The vacuum generated inthe plenum 562 draws air from each of the conduits connected thereto tosuction up loose particulates proximate to the air intake port 556 andto draw waste liquid up from the cleaning surface via the air conduits834, 836 and 666, and via the vacuum chamber 664 and the suction ports668. The loose particulates and waste liquid are drawn into the plenum562 and fall into the waste container, compartment, or tank D.

Referring to FIGS. 1, 3, 16 and 17 the integrated liquid storagecontainer or tank 800 attaches to a top side of the robot chassis 200 bya hinge element 202. The hinge element 202 is pivotally attached to therobot chassis 200 at an aft edge thereof. The liquid storage container800 is removable from the robot chassis 200 by a user and the user mayfill the cleaning fluid supply container S with clean water and ameasured volume of cleaning fluid such as soap or detergent. The usermay also empty waste from the waste container, compartment, or tank Dand flush out the waste container if needed.

To facilitate handling, the integrated liquid storage tank 800 includesa user graspable handle 162 formed integral with the cover assembly 818at a forward edge of the robot 100. The handle 162 includes a pivotelement 163 attached thereto by a hinge arrangement to the coverassembly 818. In one mode of operation, a user may grasp the handle 162to pick up the entire robot 100 thereby. In a preferred embodiment, therobot 100 weights approximately 3-5 kg, (6.6-11 pounds), when filledwith liquids, and can be easily carried by the user in one hand.

In a second mode of operation, the handle 162 is used to remove theintegrated tank 800 from the chassis 200. In this mode, the user pressesdown on an aft edge of the handle 162 to initially pivot the handledownward. The action of the downward pivot releases a latchingmechanism, not shown, that attaches a forward edge of the liquid storagecontainer or tank 800 to the robot chassis 200. With the latchingmechanism unlatched the user grasps the handle 162 and lifts verticallyupwardly. The lifting force pivots the entire container assembly 800about a pivot axis 204, provided by a hinge element which pivotallyattached to the aft edge of the chassis 200. The hinge element 202supports the aft end of the integrated liquid storage container 800 onthe chassis 200 and further lifting of the handle rotates the hingeelement 202 to an open position that facilities removal of the containerassembly 800 from the chassis 200. In the open position, the forwardedge of the liquid storage container 800 is elevated such that furtherlifting of the handle 162 lifts the liquid storage tank 800 out ofengagement with the hinge element 202 and separates it from the robot100.

As shown in FIG. 17, the integrated liquid storage container 800 isformed with recessed aft exterior surfaces forming a detent area 164 andthe detent area 164 is form matched to a receiving area of the hingeelement 202. As shown in FIG. 3, the hinge element receiving areacomprises a clevis-like cradle having upper and lower opposed walls 204and 206 form matched to engage with and orient the storage container ortank detent area 164. The alignment of the detent area 164 and the hingewalls 204 and 206 aligns the integrated storage container 800 with therobot chassis 200 and with the latching mechanism used to attach thecontainer forward edge to the chassis 200. In particular, the lower wall206 includes alignment rails 208 form-matched to mate with grooves 808formed on the bottom side of the detent area 164. In FIG. 3, the hingeelement 202 is shown pivoted to a fully open position for loading andunloading the storage container or tank 800. The loading and unloadingposition is rotated approximately 75° from a closed or operatingposition; however, other loading and unloading orientations arecontemplated. In the loading and unloading position, the storagecontainer detent area 164 is easily engaged or disengaged from theclevis-like cradle of the hinge element 202. As shown in FIG. 1, theintegrated liquid storage tank 800 and the hinge element 202 areconfigured to provide finished external surfaces that integrate smoothlyand stylishly with other external surfaces of the robot 100. Moreimportantly, as noted above, the integrated liquid storage tankmaximizes internal storage volume while permitting the robot to operateautonomously without sharp edges or corners that catch on walls,corridors, obstacles, or room corners.

Two access ports are provided on an upper surface of the liquid storagecontainer or tank 800 in the detent area 164 and these are shown inFIGS. 16 and 17. The access ports are located in the detent area 164 soas to be hidden by the hinge element upper wall 204 when the liquidstorage tank assembly 800 is in installed in the robot chassis 200. Aleft access port 166 provides user access to the waste container,compartment, or tank D through the plenum 562. A right access port 168provides user access to the cleaning fluid storage container S. The leftand right access ports 166, 168 are sealed by user removable tank capsthat may be color or form coded to be readily distinguishable.

Transport Drive System 900

In a preferred embodiment, the robot 100 is supported for transport overthe cleaning surface by a three-point transport system 900. Thetransport system 900 comprises a pair of independent rear transportdrive wheel modules 902 on the left side, and 904 on the right side,attached to the chassis 200 aft of the cleaning modules. In a preferredembodiment, the rear independent drive wheels 902 and 904 are supportedto rotate about a common drive axis 906 that is substantially parallelwith the transverse axis 108. However, each drive wheel may be cantedwith respect to the transverse axis 108 such that each drive wheel hasits own drive axis orientation. The drive wheel modules 902 and 904 areindependently driven and controlled by the master controller 300 toadvance the robot in any desired direction. The left drive module 902 isshown protruding from the underside of the chassis 200 in FIG. 3 and theright drive module 904 is shown mounted to a top surface of the chassis200 in FIG. 4. In a preferred embodiment, each of the left and rightdrive modules 902 and 904 is pivotally attached to the chassis 200 andforced into engagement with the cleaning surface by leaf springs 908,shown in FIG. 3. The leaf springs 908 are mounted to bias the each reardrive module to pivot downwardly toward the cleaning surface when thedrive wheel goes over a cliff or is otherwise lifted from the cleaningsurface. A wheel sensor associated with each drive wheel senses when awheel pivots down and sends a signal to the master controller 300.

The drive wheels of the present invention are particularly configuredfor operating on wet soapy surfaces. In particular, as shown in FIG. 20,each drive wheel 1100 comprises a cup shaped wheel element 1102, whichattaches to the a drive wheel module, 902 and 904. The drive wheelmodule includes a drive motor and drive train transmission for drivingthe drive wheel for transport. The drive wheel module may also includesensor for detecting wheel slip with respect to the cleaning surface.

The cup shaped wheel elements 1102 is formed from a stiff material suchas a hard molded plastic to maintain the wheel shape and to providestiffness. The cup shaped wheel element 1102 provides an outer diameter1104 sized to receive an annular tire element 1106 thereon. The annulartire element 1106 is configured to provide a non-slip high frictiondrive surface for contacting the wet cleaning surface and formaintaining traction on the wet soapy surface.

In one embodiment, the annular tire element 1106 has an internaldiameter 1108 of approximately 37 mm and is sized to fit appropriatelyover the outer diameter 1104. The tire may be bonded, taped or otherwiseinterference fit to the outer diameter 1104 to prevent slipping betweenthe tire inside diameter 1108 and the outside diameter 1104. The tireradial thickness 1110 is approximately 3 mm. The tire material is achloroprene homopolymer stabilized with thiuram disulfide black with adensity of 14-16 pounds per cubic foot, or approximately 15 pounds percubic foot foamed to a cell size of 0.1 mm plus or minus 0.02 mm. Thetire has a post-foamed hardness of about 69 to 75 Shore 00. The tirematerial is sold by Monmouth Rubber and Plastics Corporation under thetrade name DURAFOAM DK5151HD.

Other tire materials are contemplated, depending on the particularapplication, including, for example, those made of neoprene andchloroprene, and other closed cell rubber sponge materials. Tires madeof polyvinyl chloride (PVC) and acrylonitrile-butadiene (ABS) (with orwithout other extractables, hydrocarbons, carbon black, and ash) mayalso be used. Additionally, tires of shredded foam construction mayprovide some squeegee-like functionality, as the tires drive over thewet surface being cleaned. Tires made from materials marketed under thetrade names RUBATEX R411, R421, R428, R451, and R4261 (manufactured andsold by Rubatex International, LLC); ENSOLITE (manufactured and sold byArmacell LLC); and products manufactured and sold by AmericanConverters/VAS, Inc.; are also functional substitutions for the DURAFOAMDK5151 HD identified above.

In certain embodiments, the tire material may contain natural rubber(s)and/or synthetic rubber(s), for example, nitrile rubber (acrylonitrile),styrene-butadiene rubber (SBR), ethylene-propylene rubber (EPDM),silicone rubber, fluorocarbon rubber, latex rubber, silicone rubber,butyl rubber, styrene rubber, polybutadiene rubber, hydrogenated nitrilerubber (HNBR), neoprene (polychloroprene), and mixtures thereof.

In certain embodiments, the tire material may contain one or moreelastomers, for example, polyacrilics (i.e. polyacrylonitrile andpolymethylmethacrylate (PMMA)), polychlorocarbons (i.e. PVC),polyfluorocarbons (i.e. polytetrafluoromethylene), polyolefins (i.e.polyethylene, polypropylene, and polybutylene), polyesters (i.e.polyetheylene terephthalate and polybutylene terephthalate),polycarbonates, polyamides, polyimides, polysulfones, and mixturesand/or copolymers thereof. The elastomers may include homopolymers,copolymers, polymer blends, interpenetrating networks, chemicallymodified polymers, grafted polymers, surface-coated polymers, and/orsurface-treated polymers.

In certain embodiments, the tire material may contain one or morefillers, for example, reinforcing agents such as carbon black andsilica, non-reinforcing fillers, sulfur, cross linking agents, couplingagents, clays, silicates, calcium carbonate, waxes, oils, antioxidants(i.e. para-phenylene diamine antiozonant (PPDA), octylateddiphenylamine, and polymeric 1,2-dihydro-2,2,4-trimethylquinoline), andother additives.

In certain embodiments, the tire material may be formulated to haveadvantageous properties, for example, desired traction, stiffness,modulus, hardness, tensile strength, impact strength, density, tearstrength, rupture energy, cracking resistance, resilience, dynamicproperties, flex life, abrasion resistance, wear resistance, colorretention, and/or chemical resistance (i.e. resistance to substancespresent in the cleaning solution and the surface being cleaned, forexample, dilute acids, dilute alkalis, oils and greases, aliphatichydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, and/oralcohols).

It is noted that cell size of the closed cell foam tires may impactfunctionality, in terms of traction, resistance to contaminants,durability, and other factors. Cell sizes ranging from approximately 20μm to approximately 400 μm may provide acceptable performance, dependingon the weight of the robot and the condition of the surface beingcleaned. Particular ranges include approximately 20 μm to approximately120 μm, with a mean cell size of 60 μm, and more particularlyapproximately 20 μm to approximately 40 μm, for acceptable tractionacross a variety of surface and contaminant conditions.

In certain embodiments, the tires are approximately 13 mm wide, althoughwider tires may provide additional traction. As indicated above, tiresmay be approximately 3 mm thick, although tires of 4 mm-5 mm inthickness or more may be utilized for increased traction. Thinner tiresof approximately 1½ mm and thicker tires of approximately 4½ mm may bebeneficial, depending on the weight of the robot, operating speed,movement patterns, and surface textures. Thicker tires may be subject tocompression set. If the cleaning robot is heavier, larger tires may bedesirable nonetheless. Tires with outer rounded or square edges may alsobe employed.

To increase traction, the outside diameter of the tire can be siped.Siping generally provides traction by (a) reducing the transportdistance for fluid removal from the contact patch by providing a voidfor the fluid to move into, (b) allowing more of the tire to conform tothe floor, thereby increasing tread mobility, and (c) providing a wipingmechanism that aids in fluid removal. In at least one instance, the term“siped” refers to slicing the tire material to provide a pattern of thingrooves 1110 in the tire outside diameter. In one embodiment, eachgroove has a depth of approximately 1.5 mm and a width or approximately20 to 300 microns. The siping may leave as little as ½ mm or less oftire base, for example, 3½ mm deep siping on a 4 mm thick tire. Thegroove pattern can provide grooves that are substantially evenly spacedapart, with approximately 2 to 200 mm spaces between adjacent grooves.“Evenly spaced” may mean, in one instance, spaced apart and with arepeating pattern, not necessarily that every siped cut is the samedistance from the next. The groove cut axis makes an angle G with thetire longitudinal axis. The angle G ranges from about 10-50 degrees, incertain embodiments.

In other embodiments, the siping pattern is a diamond-shaped cross hatchat 3.5 mm intervals, which may be cut at alternating 45 degree angles(+/−10 degrees) from the rotational axis. Substantially circumferentialsiping, siping that forces away liquid via channels, and other sipingpatterns are also contemplated. Depth and angle of siping may bemodified, depending on particular applications. Moreover, whileincreased depth or width of siping may increase traction, this benefitshould be balanced against effecting the structural integrity of thetire foam. In certain embodiments, for example, it has been determinedthat 3 mm-4 mm thick tires with diamond crossed siping at 7 mm intervalsprovides good tire traction. Larger tires may accommodate a finerpattern, deeper siping, and/or wider siping. Additionally, particularlywide tires or tires made from certain materials may not require anysiping for effective traction. While certain siping patterns may be moreuseful on wet or dry surfaces, or on different types of surfaces, sipingthat provides consistent traction across a variety of applications maybe the most desirable for a general purpose robot cleaner.

The various tire materials, sizes, configurations, siping, etc., impactthe traction of the robot during use. In certain embodiments, therobot's wheels roll directly through the spray of cleaning solution,which effects the traction, as do the contaminants encountered duringcleaning. A loss of traction of the wheels may cause operatinginefficiencies in the form of wheel slippage, which can lead to therobot deviating from its projected path. This deviation can increasecleaning time and reduce battery life. Accordingly, the robot's wheelsshould be of a configuration that provides good to excellent traction onall surfaces, with the smallest corresponding motor size.

Typical contaminants encountered during cleaning include chemicals,either discharged by the robot or otherwise. Whether in a liquid state(e.g., pine oil, hand soap, ammonium chloride, etc.) or a dry state(e.g., laundry powder, talcum powder, etc.), these chemicals may breakdown the tire material. Additionally, the robot tires may encountermoist or wet food-type contaminants (e.g., soda, milk, honey, mustard,egg, etc.), dry contaminants (e.g., crumbs, rice, flour, sugar, etc.),and oils (e.g., corn oil, butter, mayonnaise, etc.). All of thesecontaminants may be encountered as residues, pools or slicks, or driedpatches. The tire materials described above have proven effective inresisting the material breakdown caused by these various chemicals andoils. Additionally, the cell size and tire siping described has provenbeneficial in maintaining traction while encountering both wet and drycontaminants, chemical or otherwise. Dry contaminants at certainconcentrations, however, may become lodged within the siping. Thechemical cleaner used in the device, described below, also helpsemulsify certain of the contaminants, which may reduce the possibledamage caused by other chemical contaminants by diluting thosechemicals.

In addition to contaminants that may be encountered during use, thevarious cleaning accessories (e.g., brushes, squeegees, etc.) of thedevice effect the traction of the device. The drag created by thesedevices, the character of contact (i.e., round, sharp, smooth, flexible,rough, etc.) of the devices, as well as the possibility of slippagecaused by contaminants, varies depending on the surface being cleaned.Limiting the areas of contact between the robot and the surface beingcleaned reduces attendant friction, which improves tracking and motion.One and one-half pounds of drag force versus three to five pounds ofthrust has proven effective in robots weighing approximately 5-15pounds. Depending on the weight of the robot cleaner, these numbers mayvary, but it is noted that acceptable performance occurs at less thanabout 50% drag, and is improved with less than about 30% drag.

The tire materials (and corresponding cell size, density, hardness,etc.), siping, robot weight, contaminants encountered, degree of robotautonomy, floor material, and so forth, all impact the total tractioncoefficients of the robot tires. For certain robot cleaners, thecoefficient of traction (COT) for the minimum mobility threshold hasbeen established by dividing a two lb. drag (as measured during squeegeetesting) by six lbs. of normal force, as applied to the tires. Thus,this minimum mobility threshold is approximately 0.33. A targetthreshold of 0.50 was determined by measuring the performance ofshredded black foam tires. Traction coefficients of many of thematerials described above fell within a COT range of 0.25 to 0.47, thuswithin the acceptable range between the mobility threshold and thetarget threshold. Additionally, tires that exhibit little variability intraction coefficients between wet and dry surfaces are desirable, giventhe variety of working conditions to which a cleaning robot is exposed.

The robot cleaning device may also benefit by utilizing sheaths orbooties that at least partially or fully surround the tires. Absorbentmaterials, such as cotton, linen, paper, silk, porous leather, chamois,etc., may be used in conjunction with the tires to increase traction.Alternatively, these sheaths may replace rubberized wheels entirely, bysimply mounting them to the outer diameter 1104 of the cup shaped wheelelement 1102. Whether used as sheaths for rubber tires or as completereplacements for the rubber tires, the materials may be interchangeableby the user or may be removed and replaced via automation at a base orcharging station. Additionally, the robot may be provided to the enduser with sets of tires of different material, with instructions to useparticular tires on particular floor surfaces.

The cleaning solution utilized in the robot cleaner should be able toreadily emulsify contaminants and debond dried waste from surfaces,without damaging the robot or surface itself. Given the adverse effectsdescribed above with regard to robot tires and certain chemicals, theaggressiveness of the cleaning solution should be balanced against theshort and long-term negative impacts on the tires and other robotcomponents. In view of these issues, virtually any cleaning materialthat meets the particular cleaning requirements may be utilized with thecleaning robot. In general, for example, a solution that includes both asurfactant and a chelating agent may be utilized. Additionally, a pHbalancing agent such as citric acid may be added. Adding a scent agent,such as eucalyptus, lavender, and/or lime, for example, may improve themarketability of such a cleaner, contributing to the perception on thepart of the consumer that the device is cleaning effectively. A blue,green, or other noticeable color may also help distinguish the cleanerfor safety or other reasons. The solution may also be diluted and stilleffectively clean when used in conjunction with the robot cleaner.During operation, there is a high likelihood that the robot cleaner maypass over a particular floor area several times, thus reducing the needto use a full strength cleaner. Also, diluted cleaner reduces the wearissues on the tires and other components, as described above. One suchcleaner that has proven effective in cleaning, without causing damage tothe robot components, includes alkyl polyglucoside (for example, at 1-3%concentration) and tetrapotassium ethylenediamine-tetraacetate(tetrapotassium EDTA) (for example, at 0.5-1.5% concentration). Duringuse, this cleaning solution is diluted with water to produce a cleaningsolution having, for example, approximately 3-6% cleaner andapproximately 94-97% water. Accordingly, in this case, the cleaningsolution actually applied to the floor may be as little as 0.03% to0.18% surfactant and 0.01 to 0.1% chelating agent. Of course, othercleaners and concentrations thereof may be used with the disclosed robotcleaner.

For example, the families of surfactants and chelating agents disclosedin U.S. Pat. No. 6,774,098, the disclosure of which is herebyincorporated by reference in its entirety, are also suitable forapplication in the robot having the tire materials and configurationsdisclosed. To balance the aggressiveness of the cleaners disclosed inthe '098 patent with the wear caused on the machine components, however,it is preferred that the cleaning agents should (i) include no solvent,or include solvent at a percentage lower than that of the chelatingagent of an alcohol solvent, or have the disclosed solvents in ½ to1/100 the concentrations, and/or (ii) be further diluted fordeterministic single pass, deterministic repeat passes, or randommultipass use in a robot by 20%+/−15% (single pass), 10%+/−8% (repeatpass), and from 5% to 0.1% (random multipass) respectively, of theconcentrations disclosed; and/or (iii) be further combined with ananti-foaming agent known to be compatible with the selected surfactantand chelating agent in percentages the same as or lower than commercialcarpet cleaners, e.g., less than 5% of silicone emulsion, and/or (iv)replaced with or compatibly mixed with an odor remover of viablebacterial cultures.

In certain embodiments, the cleaning solution utilized in the robotcleaner includes (or is) one or more embodiments of the “hard surfacecleaner” described in U.S. Pat. No. 6,774,098, preferably subject to(i), (ii), (iii), and/or (iv) above. Certain embodiments of the “hardsurface cleaner” in U.S. Pat. No. 6,774,098, are described in thefollowing paragraphs.

In one embodiment, the hard surface cleaner comprises: (a) a surfactantsystem consisting of amine oxides within the general formula (I):

or quaternary amine salts within the general formula (II):

or combinations of the foregoing amine oxides and quaternary aminesalts; and (b) a very slightly water-soluble polar organic compoundhaving a water solubility ranging from about 0.1 to 1.0 weight percent,a weight ratio of the very slightly water-soluble polar organic compoundto the surfactant system ranging from about 0.1:1 to about 1:1, whereinR¹ and R² are the same or different and are selected from the groupconsisting of methyl, ethyl, propyl, isopropyl, hydroxyethyl andhydroxypropyl, R³ is selected from the group consisting of straightchain alkyls, branched chain alkyls, straight chain heretroalkyls,branched chain heteroalkyls and alkyl ethers, each having from about 10to 20 carbon atoms, R⁴ is selected from the group consisting of alkylgroups having from 1 to about 5 carbon atoms, and X is a halogen atom.

In another embodiment, the hard surface cleaner comprises: (a) either(i) a combination of a nonionic surfactant and a quaternary ammoniumsurfactant or (ii) an amphoteric surfactant, the total amount of thesurfactant being present from about 0.001-10%, wherein the nonionicsurfactant is selected from the group consisting of an alkoxylatedalkylphenol ether, an alkoxylated alcohol, or a semi-polar nonionicsurfactant which itself is selected from the group consisting ofmono-long-chain alkyl, di-short-chain trialkyl amine oxides,alkylamidodialkyl amine oxides, phosphine oxides and sulfoxides; (b) nomore than 50% of at least one water-soluble or dispersible organicsolvent having a vapor pressure of at least 0.001 mm Hg at 25° C.; (c)0.01-25% of tetraammonium ethylenediamine-tetraacetate (tetraammoniumEDTA) as a chelating agent; and (d) water.

In yet another embodiment, the hard surface cleaner comprises (a) asurfactant selected from the group consisting of anionic, nonionicsurfactants, and mixtures thereof, with optionally, a quaternaryammonium surfactant, the total amount of surfactant being present fromabout 0.001-10% by weight; (b) at least one water-soluble or dispersibleorganic solvent having a vapor pressure of at least 0.001 mm Hg at 25°C., the at least one organic solvent being selected from the groupconsisting of alkanols, diols, glycol ethers, and mixtures thereofpresent in an amount from about 1% to 50% by weight of the cleaner; (c)tetrapotassium ethylenediamine-tetraacetate (potassium EDTA) as achelating agent, the potassium EDTA present from about 0.01-25%weight-of the cleaner; and (d) water.

In still another embodiment, the hard surface cleaner comprises (a) anonionic surfactant with optionally, a quaternary ammonium surfactant,the total amount of the surfactant being present from about 0.001-10%,wherein the nonionic surfactant is selected from the group consisting ofan alkoxylated alkylphenol ether, an alkoxylated alcohol, or asemi-polar nonionic surfactant which itself is selected from the groupconsisting of mono-long-chain alkyl, di-short-chain trialkyl amineoxides, alkylamidodialkyl amine oxides, phosphine oxides and sulfoxides;(b) no more than 50% of at least one water-soluble or dispersibleorganic solvent having a vapor pressure of at least 0.001 mm Hg at 25°C.; (c) 0.01-25% of tetraammonium ethylenediamine-tetraacetate(tetraammonium EDTA) as a chelating agent; and (d) water.

In certain embodiments, the hard surface cleaner has a viscosity of lessthan about 100 cps and comprises: (a) at least about 85% water, in whichis dissolved (b) at least about 0.45 equivalent per kilogram of aninorganic anion which, when combined with calcium ion, forms a saltwhich has a solubility of not more than 0.2 g/100 g water at 25° C.,wherein the anion is carbonate, fluoride, or metasilicate ion, or amixture of such anions, (c) at least 0.3% by weight, based on the weightof the composition, of a detersive surfactant including an amine oxideof the form RR¹R²N→O wherein R is C₆-C₁₂ alkyl and R¹ and R² areindependently C₁₋₄ alkyl or C₁₋₄ hydroxyalkyl, and (d) at least about0.5 weight percent of a bleach, based upon the weight of thecomposition, wherein the cleaning composition is alkaline andessentially free of chelating agents, phosphorous-containing salt, andabrasive.

In certain embodiments, the cleaning solution utilized in the robotcleaner includes (or is) one or more embodiments of the hard surfacecleaners described in U.S. Pat. Nos. 5,573,710, 5,814,591, 5,972,876,6,004,916, 6,200,941, and 6,214,784, all of which are incorporatedherein by reference.

U.S. Pat. No. 5,573,710 discloses an aqueous multiple-surface cleaningcomposition which can be used for the removal of grease and stains fromhard surfaces or hard fibrous substrates such as carpet and upholstery.The composition contains (a) a surfactant system consisting of amineoxides within the general formula (I):

or quaternary amine salts within the general formula (II):

or combinations of the foregoing amine oxides and quaternary aminesalts; and (b) a very slightly water-soluble polar organic compound. Thevery slightly water-soluble polar organic compound may have a watersolubility ranging from about 0.1 to 1.0 weight percent, and the weightratio of the very slightly water-soluble polar organic compound to thesurfactant system may range from about 0.1:1 to about 1:1. R¹ and R² maybe selected from the group consisting of methyl, ethyl, propyl,isopropyl, hydroxyethyl and hydroxypropyl. R¹ and R² may be the same ordifferent. R³ may be selected from the group consisting of straightchain alkyls, branched chain alkyls, straight chain heretroalkyls,branched chain heteroalkyls and alkyl ethers, each having from about 10to 20 carbon atoms. R⁴ may be selected from the group consisting ofalkyl groups having from 1 to about 5 carbon atoms. X is a halogen atom.

In certain cases, the composition further includes a water solubleorganic compound in an amount effective to reduce streaking. The watersoluble organic compound may be selected from water soluble glycolethers and water soluble alkyl alcohols. The water soluble organiccompound may have a water solubility of at least 14.5 weight percent.The weight ratio of the surfactant system to the water soluble organiccompound may range from about 0.033:1 to about 0.2:1.

U.S. Pat. No. 5,814,591 describes an aqueous hard surface cleaner withimproved soil removal. The cleaner includes (a) either (i) a nonionic,an amphoteric surfactant, or a combination thereof, or (ii) a quaternaryammonium surfactant, the surfactants being present in acleaning-effective amount; (b) at least one water-soluble or dispersibleorganic solvent having a vapor pressure of at least 0.001 mm Hg at 25°C., the at least one organic solvent present in a solubilizing- ordispersion-effective amount; (c) ammonium ethylenediamine-tetraacetate(ammonium EDTA) as a chelating agent, the ammonium EDTA present in anamount effective to enhance soil removal in the cleaner; and (d) water.The total surfactant maybe present in an amount from about 0.001-10%. Ina concentrated product, the surfactant may be present up to 20% byweight. The nonionic surfactant may be selected from the groupconsisting of an alkoxylated alkylphenol ether, an alkoxylated alcohol,or a semi-polar nonionic surfactant which itself is selected from thegroup consisting of mono-long-chain alkyl, di-short-chain trialkyl amineoxides, alkylamidodialkyl amine oxides, phosphine oxides and sulfoxides.The at least one water-soluble or dispersible organic solvent may bepresent in an amount of no more than 50% by weight of the cleaner. Theammonium EDTA may be a tetraammonium EDTA and present in an amount ofabout 0.01-25% by weight of the total cleaner.

U.S. Pat. No. 5,972,876 discloses an aqueous hard surface cleanercomprising (a) a surfactant selected from the group consisting ofanionic, nonionic surfactants, and mixtures thereof, with optionally, aquaternary ammonium surfactant, the total amount of surfactant beingpresent in a cleaning-effective amount; (b) at least one water-solubleor dispersible organic solvent having a vapor pressure of at least 0.001mm Hg at 25° C., the organic solvent being present in a solubilizing- ordispersion-effective amount; (c) tetrapotassiumethylenediamine-tetraacetate (potassium EDTA) as a chelating agent, thepotassium EDTA present in an amount effective to enhance soil removal inthe cleaner; and (d) water. The total amount of surfactant may bepresent from about 0.001-10% by weight. The at least one organic solventmay be selected from the group consisting of alkanols, diols, glycolethers, and mixtures thereof, and is present in an amount from about 1%to 50% by weight of the cleaner. The potassium EDTA may be present fromabout 0.01-25% weight-of the cleaner.

U.S. Pat. No. 6,004,916 discloses an aqueous, hard surface cleaner whichcontains (a) either a nonionic or amphoteric surfactant with optionally,a quaternary ammonium surfactant, the surfactants being present in acleaning-effective amount; (b) at least one water-soluble or dispersibleorganic solvent having a vapor pressure of at least 0.001 mm Hg at 25°C., the at least one organic solvent present in a solubilizing- ordispersion-effective amount; (c) ammonium ethylenediamine-tetraacetate(ammonium EDTA) as a chelating agent, the ammonium EDTA present in anamount effective to enhance soil removal in the cleaner; and (d) water.The surfactant may be a nonionic surfactant with optionally, aquaternary ammonium surfactant. The nonionic surfactant may be selectedfrom the group consisting of an alkoxylated alkylphenol ether, analkoxylated alcohol, or a semi-polar nonionic surfactant which itself isselected from the group consisting of mono-long-chain alkyl,di-short-chain trialkyl amine oxides, alkylamidodialkyl amine oxides,phosphine oxides and sulfoxides. The total amount of the surfactant maybe present from about 0.001-10%. The at least one water-soluble ordispersible organic solvent may be present in an amount of no more than50% by weight of the cleaner. The ammonium EDTA may be a tetraammoniumEDTA which is present in an amount from 0.01-25% by weight of the totalcleaner.

U.S. Pat. No. 6,200,941 discloses a diluted hard surface cleaningcomposition. The cleaning composition contains (a) at least about 85%water, in which is dissolved (b) at least about 0.45 equivalent perkilogram of an inorganic anion which, when combined with calcium ion,forms a salt which has a solubility of not more than 0.2 g/100 g waterat 25° C.; (c) at least 0.3% by weight, based on the weight of thecomposition, of a detersive surfactant. The composition preferably has aviscosity of less than about 100 cps. The anion may be carbonate,fluoride, or metasilicate ion, or a mixture of such anions. Thedetersive surfactant may include an amine oxide of the form RR¹R²N→Owherein R is C₆-C₁₂ alkyl and R¹ and R² are independently C₁₋₄ alkyl orC₁₋₄ hydroxyalkyl. The composition may further contain at least about0.5 weight percent of a bleach, based upon the weight of thecomposition. In one case, the cleaning composition is alkaline andessentially free of chelating agents, phosphorous-containing salt, andabrasive.

U.S. Pat. No. 6,214,784 describes a composition similar to thatdisclosed in U.S. Pat. No. 5,972,876. The composition may includedipotassium carbonate as a buffers.

Optionally, the cleaning fluid may be used to cool the motor or themotor may be used to heat the cleaning fluid. The motor used to turn themain cleaning brush dissipates considerable energy in the form of heat.This heat reduces motor and electronics life. It is possible to duct thecleaning fluid around this motor so that the heat is transferred fromthe motor to the heat. This may improve cleaning performance and reducestress on the motor. A structure would include ducting, heat transfercompounds, and heat conductive materials for the ducting and/or motorparts in contact with the ducting. In addition, the use of a wet rotormotor for the fluid pump or brush drive would allow the motor to besubmersed in the clean tank which could simplify connections as well asdeposit waste heat into the cleaning fluid.

The nose wheel module 960, shown in exploded view in FIG. 18 and insection view in FIG. 19, includes a nose wheel 962 housed in a casterhousing 964 and attached to a vertical support assembly 966. The nosewheel module 960 attaches to the chassis 200 forward of the cleaningmodules and provide a third support element for supporting the chassis200 with respect to the cleaning surface. The vertical support assembly966 is pivotally attached to the caster housing 964 at a lower endthereof and allows the caster housing to pivot away from the chassis 200when the chassis is lifted from the cleaning surface or when the nosewheel goes over a cliff. A top end of the vertical support assembly 966passes through the chassis 200 and is rotatably with respect thereto toallow the entire nose wheel module 960 to rotate freely about asubstantially vertical axis as the robot 100 is being transported overthe cleaning surface by the rear transport drive wheels 902 and 904.Accordingly, the nose wheel module is self-aligning with respect to thedirection of robot transport.

The chassis 200 is equipped with a nose wheel mounting well 968 forreceiving the nose wheel module 960 therein. The well 968 is formed onthe bottom side of the chassis 200 at a forward circumferential edgethereof. The top end of the vertical support assembly 966 passes througha hole through the chassis 200 and is captured in the hole to attach thenose wheel to the chassis. The top end of the vertical support assembly966 also interfaces with sensor elements attached to the chassis 200 onits top side.

The nose wheel assembly 962 is configured with a molded plastic wheel972 having axle protrusions 974 extending therefrom and is supported forrotation with respect to the caster housing 964 by opposed co-alignedaxle holes 970 forming a drive wheel rotation axis. The plastic wheel972 includes with three circumferential grooves in its outer diameter. Acenter groove 976 is providing to receive a cam follower 998 therein.The plastic wheel further includes a pair of symmetrically opposedcircumferential tire grooves 978 for receiving an elastomeric o-ring 980therein. The elastomeric o-rings 980 contacts the cleaning surfaceduring operation and the o-ring material properties are selected toprovide a desired friction coefficient between the nose wheel and thecleaning surface. The nose wheel assembly 962 is a passive element thatis in rolling contact with the cleaning surface via the o-rings 980 androtates about its rotation axis formed by the axle protrusion 974 whenthe robot 100 is transported over the cleaning surface.

The caster housing 964 is formed with a pair of opposed clevis surfaceswith coaligned opposed pivot holes 982 formed therethrough for receivingthe vertical support assembly 966 therein. A vertical attaching member984 includes a pivot element 986 at its bottom end for installingbetween the clevis surfaces. The pivot element 986 includes a pivot axisbore 988 formed therein for alignment with the co-aligned pivot hole982. A pivot rod 989 extends through the co-aligned pivot holes 982 andis press fit within the pivot axis bore 988 and captured therein. Atorsion spring 990 installs over the pivot rod 988 and provides a springforce that biases the caster housing 964 and nose wheel assembly 962 toa downwardly extended position forcing the nose wheel 962 to rotate toan orientation that places the nose wheel 962 more distally below thebottom surface of the chassis 200. The downwardly extended position is anon-operating position. The spring constant of the torsion spring 990 issmall enough that the weight of the robot 100 overcomes its biasingforce when the robot 100 robot is placed onto the cleaning surface forcleaning. Alternately, when the nose wheel assembly goes over a cliff,or is lifted off the cleaning surface, the torsion spring biasing forcepivots the nose wheel to the downwardly extended non-operating position.This condition is sensed by a wheel down sensor, described below, and asignal is sent to the master controller 300 to stop transport or toinitiate some other action.

The vertical attaching member 984 includes a hollow vertical shaftportion 992 extending upward from the pivot element 986. The hollowshaft portion 992 passes through the hole in the chassis 200 and iscaptured therein by an e-ring retainer 994 and thrust washer 996. Thisattaches the nose wheel assembly 960 to the chassis and allows it torotate freely about a vertical axis when the robot is being transported.

The nose wheel module 960 is equipped with sensing elements thatgenerate sensor signals used by the master control module 300 to countwheel revolutions, to determine wheel rotational velocity, and to sensea wheel down condition, i.e. when the caster 964 is pivoted downward bythe force of the torsion spring 990. The sensors generate a wheelrotation signal using a cam following plunger 998 that include a sensorelement that moves in response to wheel rotation. The cam follower 998comprises an “L” shaped rod with the a vertical portion being movablysupported inside the hollow shaft 992 thus passing through the hole inthe chassis 200 to extend above the top surface thereof. The lower endof the rod 992 forms a cam follower that fits within the wheel centercircumferential groove 976 and is movable with respect thereto. The camfollower 998 is supported in contact with an offset hub 1000 shown inFIG. 18. The offset hub 1000 comprises an eccentric feature formednon-symmetrically about the nose wheel rotation axis inside thecircumferential groove 976. With each rotation of the wheel 962, theoffset hub 1000 forces and oscillation of the cam follower 998 whichmoves reciprocally along a substantially vertical axis.

FIGS. 33-35 show an alternative structure for the front caster. As shownin FIGS. 33-34, the front caster may be generally structured aspreviously described, and with a design that integrates the functions ofa stasis sensor (to determine that the undriven front caster is turning)and a wheel drop switch (to determine that it is no longer in contactwith the ground). A fishhook shaped member 998 having a vertical shaftand a horizontal hook is looped around an eccentric boss 999 formed inthe middle of the caster wheel. While the caster wheel rotates about itsrotational axis for forward motion and about the support 984 to turn,the fishhook member sensor member 998 may turn within the support 984freely (without impeding turning of the caster) but may also slidevertically within the support 984. As the actuator moves up and downsinusoidally, one sensor (as described herein, generally an optical ormagnetic “stasis” sensor near the top of the member 998) may be used totrack whether the robot moves forward. Alternatively, two sensors areused, one near each vertical end of the possible travel of the member998, i.e., separated by substantially twice the offset of the boss 999.Two sensors improve resolution. Alternatively, the two sensors may bemodeled as, or replaced with a linear sensor to provide an analogprofile over time of the wheel rotation (e.g., even with only twosensors, if placed carefully, the analog output strength of the optical,magnetic, or electrical detection of the opposite ends of the member 998can provide opposite ends of a substantially sinusoidal signal uponrotation, giving speed and limited odometry information). These areplaced according to the position of the front caster on its suspensionduring normal use of the robot. Additionally, a wheel-drop sensor(again, optical, magnetic, or the like) is placed below the stasissensors. As noted, the wheel is biased on its support housings 984, 970to pivot to move within a swinging vertical range and provide a springedsuspension. Should the robot's front wheel drop over a cliff or uponpicking up the robot, as the member 998 moves into or below the range ofthe wheel-drop sensor, this may be detected. Accordingly, the assemblywith member 998 and sensors works as a stasis sensor and a wheel-dropsensor, and may also act as a speed sensor. As noted herein, siping ofthe tire material is a cross-hatch of diagonal cuts. These cuts may beat angles from 20-70 degrees from the forward motion line of the robot.

A once per revolution wheel sensor includes a permanent magnet 1002attached to the top end of the “L” shaped rod by an attaching element1004. The magnet 1002 oscillates through a periodic vertical motion witheach full revolution of the nose wheel. The magnet 1002 generates amagnetic field which is used to interact with a reed switch, not shown,mounted to the chassis 200 in a fixed location with respect to movingmagnet 1002. The reed switch is activated by the magnetic field eachtime the magnet 1002 is in the full up position in its travel. Thisgenerates a once per revolution signal which is sensed by the mastercontroller 300. A second reed switch may also be positioned proximate tothe magnet 1002 and calibrated to generate a wheel down signal. Thesecond reed switch is positioned in a location that will be influencedby the magnetic field when the magnet 1002 drops to the non-operatingwheel down position.

Basic Form Factor

In one embodiment of robot of the present invention, the diameter of therobot circular cross-section 102 is 370 mm or 14.57 inches, i.e.,approximately 35-40 cm or 12-15 in., and the height of the robot 100above the cleaning surface is 85 mm or 3.3 inches, i.e., approximately70-100 mm or 3-4½ inches. This size will navigate household doorways,under toe kicks, and clean under many typical chairs, tables, portableislands, and stools, and behind and beside some toilets, sink stands,and other porcelain fixtures. However, the autonomous cleaning robot 100of the present invention may be built with other cross-sectionaldiameter and height dimensions, as well as with other cross-sectionalshapes, e.g. square, rectangular and triangular, and volumetric shapes,e.g. cube, bar, and pyramidal. The height of the robot is less than thatof a 10″ cabinet toe kick (approximately the height of awheelchair-accessible toe kick or European toe kicks), and preferablyless than that of a 4″ cabinet toe kick (the lowest American standard).Alternatively, the height of that portion of the robot that cleans intothe toe kick may be so limited, with the remainder of the robot beinghigher.

One embodiment of a robot according to the invention uses a highlyintegrated physical structure and is manufacturable as a mass-producedcommercial product. As shown in FIG. 1B, such an embodiment includesseveral parts: the robot body, the wet fluid tank, the battery, and acleaning head. The tank may be a structural element (for example, therobot is carried by the tank handle with the fluid full), or the robotcan be a chassis-body structure or set of self-supporting monocoquestructures. Defined in certain circumstances, monocoque may mean“substantially monocoque” or “at least partially monocoque,” and otheralternative definitions are not excluded (e.g., robots having supportingribs or frames, or including a load bearing body that could also havechassis-like elements such as cantilever support for other elements).Robots having a variety of components fall within the scope of thisinvention. On such cleaning robot includes a motor-driven brush orwiper, a first housing that accommodates a fluid tank, and a secondhousing that accommodates a steerable drive mechanism. A couplingmechanism couples the first housing to the second housing to form asubstantially cylindrical outer surface of the cleaning robot. Thecleaning robot dispenses fluid from the fluid tank and brushes or wipesa surface made wet by the fluid.

In another embodiment, the cleaning robot includes a motor-driven brushor wiper, a tank formed as a upper cylinder section that stores fluid,and a platform, formed as a lower cylinder section. The platformaccommodates a steerable drive mechanism. A coupling mechanism couplesthe tank to the platform, the upper cylinder section of the tankmatching the lower cylinder section of the platform to form asubstantially cylindrical outer surface of the cleaning robot.

The integration of a fluid tank as part of a cylindrical body enableswet cleaning to be carried out by an autonomous robot with the maximumpossible cleaning time. If the body as a whole is not cylindrical, i.e.,does not have a circular perimeter, autonomy is effected, as escape fromcorners and corridors slightly larger than the robot becomes moredifficult. By integrating the fluid tank into the robot body, tankvolume may be maximized. Other shapes of constant width (reuleauxtriangle or constant width polygon) are also possible as a perimetershape, and are considered to fall within the meaning of the term“cylindrical” for the purposes of this specification, but the circularperimeter has the maximum internal area of constant width shapes andtherefore the maximum potential fluid capacity.

Still another embodiment of the cleaning robot described herein includesa waste fluid compartment, a dispensed fluid compartment, a partiallymonocoque tank that accommodates at least one of the waste fluidcompartment or dispensed fluid compartment, and a partially monocoqueplatform that accommodates a steerable drive mechanism. A couplingmechanism couples the partially monocoque tank to the partiallymonocoque platform to form a substantially cylindrical outer surface ofthe cleaning robot. The cleaning robot brushes a surface made wet atleast in part by fluid dispensed by the cleaning robot.

Another embodiment includes a motor-driven brush or wiper, a tank thataccommodates a fluid compartment for storing fluid, a platform includinga mount that receives the tank, a fluid connection between the tank andthe platform, and a vacuum connection between the tank and the platform.A coupling mechanically engages the tank to the platform. The engagementof the coupling seals the fluid connection and the vacuum connection andforms a substantially cylindrical outer surface of the cleaning robot.The cleaning robot brushes a surface made wet at least in part by fluidfrom the fluid compartment. The fluid from the fluid compartment may be,but is not necessarily, picked up by the vacuum (which could pick upjust dry particulates before the brush or wiper).

Still another embodiment includes a motor-driven brush or wiper, amonocoque tank that accommodates a fluid compartment, and a platformincluding a pivoting mount that receives one end of the tank and that isrotatable to match the monocoque tank to the platform. A couplingmechanically engages the monocoque tank to the platform, so that theengagement of the coupling forms a substantially cylindrical outersurface of the cleaning robot. The cleaning robot brushes a surface madewet at least in part by fluid from the fluid compartment. The pivotingmount can optionally be arranged to receive the tank at the same angleas a user would carry it. If the tank hangs from a user's hand at anangle due to a handle configuration, then the tank could

Yet another embodiment of the robot cleaner includes a motor-drivenbrush or wiper, a tank that accommodates a fluid compartment for storingfluid, a platform including a mount that receives the tank, a fluidconnection between the tank and the platform, and a vacuum connectionbetween the tank and the platform. A coupling mechanically engages thetank to the platform, such that the engagement of the coupling seals thefluid connection and the vacuum connection and forms a substantiallycylindrical outer surface of the cleaning robot. The cleaning robotbrushes a surface made wet at least in part by fluid from the fluidcompartment.

In still another embodiment, the cleaning robot includes a tank thataccommodates a fluid compartment for storing fluid, a cleaning head thatincludes a motor-driven brush and a vacuum, and a platform. The platformincludes a first receptacle that receives a battery. A mount receivesthe tank so that the tank covers the battery. The battery need not bebelow the tank, it may be directly attached to the body on top or side.Additionally, the cleaning head, in one embodiment, is not removable orreplaceable unless the tank is pivoted up, since the tanks and relatedcomponents may create an interlock with the cleaning head when the tankis latched in place.

The cleaning head may be considered part of the platform, or optionallya second receptacle may receive the cleaning head from one side of theplatform. The robot may include a fluid connection between the tank andthe platform (as one example, so that the platform can dispense fluid)and a vacuum connection between the tank and the platform and/orcleaning head (as one example, so that material vacuumed by the platformcan be deposited in the tank). Either or both of the vacuum connectionand the fluid connection can be made directly between the tank and thecleaning head, e.g., by matching seals on the tank and the cleaninghead. A coupling may mechanically engage the tank to the platform, andmay seal the fluid connection and the vacuum connection.

Although all of the above combinations may use a brush or wiper, use ofa brush causes less friction than wipers; moreover, the many bristles ofa rotating brush still provide continuous and continuously repeatingcontact with a surface. The word “brush” includes pads, brushes,sponges, cloths, etc., that could be rotated, reciprocated, orbital,belt-driven, move with the robot, etc.

Although different ratios are possible, it is advantageous to maximizefluid tank volume if the fluid tank is more than 50% of the top surface,up to 50% of the side wall, and less than 50% of the bottom surface ofthe robot. However, it is more advantageous if the fluid tank is lessthan 25% of the bottom surface, and more than 75% of the top surface, asthis balances the need to support the tank with the most volume.

As noted herein, the motor-driven brush is accommodated in a cleaninghead which is removably inserted in the side of the first housing, andhas a locking, click-lock, click-in/click-out or detent mechanism tohold it in place and maintain seals and connections. This construction,allows the cleaning head to be removed without removing the tank. If thebattery is below the tank but above the body, the cleaning head can alsobe removed without removing the battery. A battery can be similarlyarranged, using a similar structure, to be removably inserted from theside of the robot, with an optional locking, click-lock,click-in/click-out or detent mechanism to maintain electricalconnections. The battery may also be integrated in either the tank orthe body, and may include one or more replaceable, rechargeable, orreplenishable batteries, fuel cells, or fuel tanks, or any combinationthereof.

The coupling mechanism for securing the tank to the body can include ahandle of the fluid tank, the entire substantially cylindrical robot, orthe tank alone being rendered portable via the fluid tank handle. Thehandle may also include a locking, click-lock, click-in/click-out ordetent mechanism. The handle as depicted herein includes a mechanismthat accommodates a push to click-lock the tank to the body, anotherpush to release the tank from the body, yet pulls up to use as a handle.The coupling mechanism may include a pivot and a lock, the pivotreceiving one end of the tank and rotating the tank to engage the lock

Many of the above embodiments utilize a tank structure that functions asboth a fluid compartment and a support or structural element of therobot. Additionally, the tank may accommodate both clean and dirty fluidcompartments, as in the depicted embodiment. Alternatively, anadditional tank may provided to separate clean and dirty fluids, and/orfor a concentrate to be mixed with water in one of the tanks. Morecompartments could be provided (e.g., a compartment for a defoamer, acompartment for fuel, etc.). The embodiment demonstrates the manner inwhich a tank or combined tank may self-support or act as a structuralmember; one of skill in the art would recognize that the same types ofcouplings and supports could be readily modified for more than one tank.

As noted herein the two compartments of the tank are arranged such thatas fluid moves from one compartment to the ground and then is picked up,the center of gravity remains substantially in place, and/or remainssubstantially over the driving wheels. The present structure usescompartments that are stacked or partially stacked on top of one anotherwith their compartment-full center of gravity within 10 cm of oneanother. Alternatively, the compartments may be concentric (concentricsuch that one is inside the other in the lateral direction); may beinterleaved (e.g., interleaved L shapes or fingers in the lateraldirection); or all of or a portion of the clean compartment may be aflexible bladder within the dirty compartment and surrounded by thedirty compartment, such that the flexible bladder compresses as cleanfluid leaves it but dirty fluid filling the dirty compartment takes theplace of the clean fluid. The flexible bladder may be a portion of thebottom of the clean tank that accordions, flexes, or expands into thedirty tank. For example, in FIG. 27, the circle sector flat portions ofthe second plastic element (tank middle) 812 to the left and/or right ofthe aperture 562 a (as depicted in FIG. 27) may be formed as a flexing,expanding, or accordion part that expands into the waste tank. For thispurpose, the plenum 562 may be arranged with straight sides in thosedirections.

Within a tank, various types of constructions of the compartments arepossible: they may be separate, be joined by a wall (as depicted), beseparate deformable compartments, or be nested compartments. Certaincompartments may be nested and deformable or may include a collapsiblewall which separates compartments. Walls separating compartments may behinged, accordion, etc., and compartments may be separated by one ormore semi permeable, osmotic or reverse osmotic membranes or otherfilters. Either of “compartment” or “tank” can be rigid, deformable, orcollapsible, except where specified otherwise. The same compartment canbe used for two different fluids in different circumstances (water andpremixed cleaner compartment; treatment or polish compartment, and thelike). Compartments within a tank may be used for water or solvent,mixed cleaning solution, concentrate, dirty fluid, dry particulate,fuel, scent, defoamer, marker, polish, treatment, wax, etc., asappropriate.

While most of the above examples have a removable tank, in analternative embodiment, the tank may be permanent. The term “coupling”means the family of mechanisms for readily mounting one thing toanother, including reversible types of couplings such as snaps, catches,latches, hooks, click-lock, detent-lock, screw-in, bayonet, Velcro, andthe like. It also includes the use of gravity and guides to hold anupper part on a lower part, or tightly-fitting compatible elastomerparts. The modifier “readily detached” generally distinguish suchsemi-permanent coupling (permanent other than for repair, e.g., screwsor bolt) from permanent couplings such as glue/welds. Semi-permanent orpermanent couplings could be more practical in the case of a largerrobot that is emptied by a dock or floor station (the above embodimentsmay include a compatible dock or floor station).

As noted above, the platform may also accommodate a spray, spreader,nozzle, capillary action, wipe-on cloth or other fluid dispensingmechanism for dispensing a fluid, and/or a brush, vacuum, squeegee,wipe-off or other cloth fluid collecting mechanism for collecting wastefluid. As used above, “made wet by the fluid” can occur before or afterthe fluid is stored by a tank (e.g., the fluid can be manually appliedby a person and picked up by the robot, or fluid can be left on thesurface by the robot to dry or evaporate, depending on the type offluid, e.g., for polishes or floor treatments). Either or both housingsmay be substantially monocoque or may include a chassis portion or lockto an added chassis portion.

In cases where a pivot holder is used, the pivot holder is metal, andhas durability and stiffness. The use of a heavy metal pivot canincrease the weight of the robot (thus pressure and mopping force) andmore significantly shift the center of gravity of the main housing tothe front or rear (as necessary, depending where the metal pivot ispositioned). If a metal handle is used at an opposite end of the robot,then the two metal parts can facilitate balancing and positioning of thecenter of gravity as desired. However, balancing and positioning can beinstead facilitated by the use of a metal supportive frame that shiftsthe center of gravity of the robot toward the wheel/belt drive contactline, or simply by a heavy weight (e.g., cast iron) placed appropriatelyto shift the center of gravity of the fluid-full robot to the wheel/beltdrive contact line.

For robots designed for coverage (including cleaning robots), it is bestto place differential drive wheels on the diameter to permit the robotto turn in place. However, it is advantageous to place the working widthor cleaning head on the diameter of a circular robot, as this will givethe widest working swath. For certain vacuuming robots manufactured byiRobot Corporation under the trademark ROOMBA, because a side brush canbe used when following walls to bring particulates within the workingwidth, the wheels are placed on the diameter of the circular perimeterfor this purpose. If the robot follows walls on the same side everytime, only one side brush is needed.

However, for a mopping robot that applies liquid, the side brush is notas effective. While the present invention contemplates the use of a dryor wet side brush substantially physically similar to that of a dry-typevacuum to assist dry cleaning or wet cleaning or both, it is notbelieved to be necessary. Additionally, placing the cleaning head on thediameter of the circular perimeter so that the width of the cleaninghead can come nearest the wall helps provide effective cleaning. In thecase of another curve of constant width, the cleaning head could beplaced on the widest span, and differential drive wheels arranged closeto the diameter of a circumcircle enclosing the robot perimeter(alternatively, such a robot could use a holonomic drive withequiangularly arranged omnidirectional wheels).

When the cleaning head is on the diameter of the circular perimeter, itmay abut the edge of the robot, thus improving edge cleaningperformance. Additionally, if the robot is controlled and configured toalways follow walls and obstacles on one dominant side, then thecleaning head need only abut one edge of the robot. Such an arrangementallows space on the non-dominant side to be used for other purposes. Inthe case of one embodiment of the robot, this on-diameter edge space isused for a gear train and engagement structure to enable the cleaninghead to be slip-engaged in cartridge fashion from one lateral side ofthe robot (from the edge cleaning/dominant side), see FIGS. 3, 3B.

The cleaning system of one specific embodiment is dry pick up, followedby fluid (wet) application, followed by fluid pick up. The reason forthe dry pick up to precede fluid application, as described herein, isprimarily so that the wet pick-up is primarily of grey water/wastefluid, and not of particulates and large loose debris, which havevarious negative effects on wet pick-up and can usually be more easilypicked up when dry.

Additional cleaning steps may be incorporated into a wet cleaning robotin accordance with the present invention. For example, a dry materialapplication step may be included after the dry pick up step, e.g., astep in which an abrasive powder, catalyst, reactant, etc., or other drymaterial is deposited and mixes with fluid (or the wet spray is turnedoff and the dry material is collected or is left for later pickup).

It would also be possible to remove the dry pick up step in the casewhere another countermeasure is adopted to deal with the possibility ofwet particulates or debris, e.g., where a wet pick up mechanismaccommodates such debris. One embodiment of the device may use ascrubbing brush that precedes a lateral-strip wet vacuum/squeegee alongthe cleaning path. As one example, in an alternative embodiment where ascrubbing brush is placed to rotate within the mouth of a vacuum anddirects debris to the mouth of the vacuum, the dry pick up step may beless important. It would also be possible to change the cleaning systemsuch that the fluid application process does not immediately precede thefluid pick up process. As one example, in an alternative embodiment afirst robot would apply fluid and a second robot would pick up thefluid, or a single robot could be configured to apply fluid in one passand remove fluid in a second pass along the same path.

It would also be possible to change the cleaning system such that thefluid pick up process is not carried out, for example in the case of awax or polish. In another embodiment, the robot could apply one kind offluid (e.g., a cleaning fluid), pick it up, and apply a second kind offluid (e.g., a wax or polish) that is not picked up.

It would also be possible to change the cleaning system such that thefluid application process applies fluid to a brush, roller, belt, web,pad, or other scrubbing medium rather than directly to the floor, andthe fluid first contacts the floor primarily as it is carried there bythe scrubbing medium.

As described herein, certain new cleaning systems are particularly wellsuited to the robotic cleaner of the invention. However, no part of theprocess or system is critical, notwithstanding that there are certaincombinations of cleaning processes that form cleaning systems that hasdistinct advantages as set forth herein. Many of the robotic, form, andconfiguration structures set forth herein are new and advantageous forany wet cleaning system (as only one example, the structures associatedwith a wet cleaning head that extends to one side edge only, where therobot always cleans on that side).

As discussed herein, the robot is preferably from about 3-5 kg whencompletely filled with fluid. For household use, the robot may be asmuch as about 10 kg. Exemplary ranges for physical dimensions of therobot are a full mass of about 2-10 kg; a cleaning width of about 10cm-40 cm within a diameter of about 20-50 cm; a wheel diameter about 3cm-20 cm; drive wheel contact line about 2 cm-10 cm for all drive wheels(two, three, four drive wheels); drive wheel contact patch for allwheels about 2 cm² or higher. An exemplary robot is less thanapproximately 4 kg empty, and less than approximately 5 kg full, andcarries approximately 1 kg (or 800-1200 ml) of clean or dirty fluid (inthe case where the robot applies fluid as well as picking it up). Thewaste tank is sized according to the efficiency of the pick-up process.For example, with a comparatively inefficient squeegee designed to orarranged to leave a predetermined amount of wet fluid on each pass(e.g., so that the cleaning fluid can dwell and progressively work onstains or dried food patches), the waste tank may be designed to beequal in size or smaller than the clean tank. A portion of the depositedfluid may never be picked up, and another portion may evaporate beforeit can be picked up. In the case where a dry pick up precedes the wetpick up, and an efficient squeegee is used (e.g., silicone), then it maybe necessary to size the waste tank to be equal to or bigger than theclean fluid tank. A proportion of the tank volume, e.g., about 5% orhigher, may also be devoted to foam accommodation or control, which canincrease the size of the waste tank.

A viable autonomous hard surface cleaning robot is under about 10 kgmass, and has at least one scrubbing or wiping member. In order toeffectively brush, wipe, or scrub the surface, the scrubbing or wipingmember creates drag, and for a robot under 10 kg, should create anaverage drag of up to about 40% of weight, but preferably less thanabout 25%. Drag forces (total drag associated with any blades,squeegees, dragging components) should not exceed about 25% of robotweight to ensure good mobility in the absence of activesuspensions/constant weight systems, as any lifting obstacle willotherwise remove weight from the tires and effect motive force. Maximumavailable traction typically is no more than about 40% of robot weighton slick surfaces with a surfactant based (low surface tension) cleaningfluid, perhaps as high as about 50% in best case situations, andtraction/thrust must exceed drag/parasitic forces. However, in order tosuccessfully navigate autonomously, to have sufficient thrust toovercome minor hazards and obstacles, to climb thresholds which mayencounter the scrubbing or brushing member differently from the wheels,and to escape from jams and other panic circumstances, the robot shouldhave a thrust/traction, provided mostly by the driven wheels, of about150% or more of average drag/parasitic force. A rotating brush,depending on the direction of rotation, can create drag or thrust, theinvention contemplates both. One example of a robot disclosed herein indetail, having a weight of about 8½ lbs, with less than 2 to 3½ lb dragcaused by brushes, wipers, squeegees, and idle wheel friction, but morethan 3 to 5½ lb thrust contributed either by drive wheels alone or bydrive wheels in combination with a forwardly rotating brush, would be anexample of a robot that may successfully clean and navigateautonomously. Sometimes weight must be added to improve traction byputting more weight on the wheels (e.g., metal handle, clevis-like pivotmount, larger motor than needed, and/or ballast in one embodiment of thepresent device). With or without added weight, one embodiment of thepresent device derives a functional percentage of thrust from aforwardly rotating brush (which is turned off generally in reverse),which is not a feature needed in a large industrial cleaner.

The width of the cleaning head for the mass of the household cleaningrobot, under 10 kg (or even under 20 kg), is remarkably different fromindustrial self-propelled cleaners. According to the embodiments of theinvention, this is from 1 cm of (wet) cleaning width for every 1 kg ofrobot mass, ideally about 5 or 6 cm of cleaning width for every kg ofrobot mass, and up to 10 cm of cleaning width for every kg of robot mass(the higher ratios generally apply to lower masses). It is difficult toapply sufficient wiping or scrubbing force with more than 10 cm ofcleaning width for every kg of robot mass; and less than 1 cm for every1 kg of robot mass leads to either an ineffective cleaning width or avery heavy robot unsuitable for consumer use, i.e., that cannot becarried easily by an ordinary (or frail) person. Self-propelledindustrial cleaning machines typically will be have 1-3 cm of cleaningwidth or less per kg machine mass.

The ratios of these dimensions or properties may implicate whether arobot under 10 kg, and in some cases under 20 kg, will be effective forgeneral household use. Although some such ratios are describedexplicitly above, certain ratios (e.g., cm squared area of wheel contactper lb of robot weight, cm of wheel contact line per lb of drag, and thelike) are expressly considered to be inherently disclosed herein, albeitlimited to the set of different robot configurations discussed herein.

Although the present disclosure discusses in detail the best materialconfiguration and geometry for tires or tracks for a robot useful on wethousehold surfaces, certain combinations of other cleaner elements withthese materials and tire geometry are particularly effective. As for thetires themselves, as discussed, one advantageous configuration would bea 3 mm foam tire thickness with 2 mm deep sipes. This configurationadequately performs when supporting no more than 3 to 4 kg per tire. Theideal combination of sipes, cell structure and absorbency for a tire isaffected by robot weight.

At least one passive wiper or squeegee is advantageous on the wetcleaning robot. For example, a wet vacuum portion should be closelyfollowed by a squeegee to build up the thickness of a deposited waterfilm for pick-up. A trailing (wet) squeegee should have sufficientflexibility and range of motion to clear any obstacle taller than 2 mm,but ideally to clear the ground clearance of the robot (in the case ofthe embodiment detailed herein, the 4½ mm minimum height or groundclearance of the robot).

Any reactionary force exhibited by the squeegee that is directionallyopposite to gravity, subtracts from available traction and should not toexceed about 20% of robot weight, ideally no more than about 10% ofrobot weight. A certain amount of edge pressure, which has an equalreactionary force, is necessary for the squeegee to wipe and collectfluid. In order to obtain an effective combination of fluid collection,reactionary force, wear, and flexible response to obstacles, thephysical parameters of the squeegee should be well controlled andbalanced. It is noted that a working edge radius of about 3/10 mm for asqueegee less than about 300 mm is particularly effective, and squeegeesof from about 1/10 to 5/10 mm working edge can be expected to be viabledepending upon other accommodations made. Wear, squeegee performance,and drag force are improved with a squeegee of substantially rectangularcross section (optionally trapezoidal) and/or about 1 mm (optionallyabout ½ mm to 1½ mm) thickness, about 90 degree corners (optionallyabout 60 to 120 degrees), parallel to the floor within about ½ mm overits working length (optionally within up to about ¾ mm), and straight towithin about 1/500 mm per unit length (optionally within up to about1/100), with a working edge equal to or less than about 3/10 mm as notedabove. Deviations from the above parameters require greater edgepressure (force opposite to gravity) to compensate, thus decreasingavailable traction.

Three exemplary wet vacuum/squeegee assemblies are disclosed herein, oneof which uses a “split squeegee,” where wet pickup is primarily providedby a vacuum channel between a forward wet squeegee and a rear wetsqueegee, and the two squeegees are separated members that can sliderelative to one another as the squeegee is deformed during use. Asdepicted in FIG. 12 herein, the rear wet squeegee to the left of thedrawing would separate from the front wet squeegee adjacent the brushwhen the cartridge is opened for cleaning. The forward wet squeegee iscrenellated on an inside surface to provide a series of vacuum channels,and the primary task of the forward wet squeegee is to appropriatelydeform to maintain the vacuum within the channels and to deliver theforward ends of the channels to the floor. The forward wet squeegee (ofa split squeegee design), maintains a constant open cross-sectional areato define the aerodynamic parameters relative to the trailing wetsqueegee. However, in order to accomplish this, the forward wet squeegeeneed only contact the floor at designated locations and does not requireedge pressure to be functional. The forward wet squeegee must be able toclear obstacles at the ground clearance of the robot, e.g., to clear anyobstacle over about 4½ mm minimum height of robot for a 4½ mm rear orwet ground clearance. The forward wet should maintains aerodynamic crosssectional areas at about 80-120%, ideally at about 90-110%, of designpoint (e.g., the projected cross sectional area in a static design) atany location along its length. Deviation of the cross sectional arearesults in inconsistent vacuum assist for the squeegee and reducescleaning performance.

When a squeegee is used with or behind a dry vacuum, the dry-vacsqueegee must have sufficient flexibility and range of motion to clearany obstacle taller than the forward ground clearance, i.e., for exampleto clear any obstacle taller than a about 6½ mm height of a forward(dry) half of the robot (in this example, the forward height may behigher or lower). Because the primary purpose of the “dry squeegee” or“doctor blade” is as an air flow guide, and not as a true doctor bladeor squeegee, despite the use of the terminology “dry squeegee” or“doctor blade” herein, the end of the dry squeegee can be optionallydesigned to be separate from the floor by, for example, 0 to about 1 mm,ideally ½ mm. Edge pressure is not necessarily required for the dryvacuum squeegee, i.e., air flow guide blade, to function properly foroptimum performance. An ideal air flow guide blade can pivot fore andaft by about 10-30 degrees, ideally 20 degrees.

When brushes or wipers are used, both static and rotational brushes orwipers must contact the floor over a broad range of surface variations(e.g., in wet cleaning scenarios, including tiled, flat, wood, deepgrout floors). This contact is accomplished according to the inventiongenerally one or both of two ways: the brush or wiper is mounted using afloating mount (e.g., on springs, elastomers, guides, or the like);and/or adequate flexibility for the designed amount of interference orengagement of the scrubbing brush or wiper to the surface. As notedabove, any reactionary force exhibited by the brushes/scrubbingapparatus that is opposite to gravity subtracts from available tractionand should not exceed about 10% of robot weight. Helix designs ofspinning brushes help to minimize forces opposite to gravity and reduceenergy requirements for rotation.

Most of the embodiments described herein, where using a rotationalbrush, use a single brush. More than one brush may be provided, e.g.,two counter-rotating brushes with one brush on either fore-aft side ofthe center line of a robot, or more. A differential rotation brush mayalso be employed. In such a case, two brushes, each substantially halfthe width of the robot at the diameter of rotation, are placed on eitherlateral side of the spin/rotation center line, each extending along halfof the diameter. Each brush is connected to a separate drive and motor,and may rotate in opposite directions or in the same direction or in thesame direction, at different speeds in either direction, which wouldprovide rotational and translational impetus for the robot.

A cleaning robot according to one embodiment of the invention is alsoprovided with a suspension system, primarily including a pivoted wheelassembly including resilience and/or damping, having a ride heightdesigned considering up and down force. The ideal suspension is capableof delivering ideally within about 2% (optionally 1-5%) of the minimumdownward force of the robot (i.e., robot mass ore weight minus upwardforces from the resilient or compliant contacting members such asbrushes/squeegees, etc). That is, the suspension is resting against“hard stops” with only about 2% of the available downward force applied(spring stops having the other 98%, optionally 95%-99%), such that anyalmost any obstacle or perturbation capable of generating an upwardforce will result in the suspension lifting or floating the robot overthe obstacle while maintaining maximum available force on the tirecontact patch. This spring force (and in corollary, robot traction) canbe maximized by having an active system that varies its force relativeto the changing robot payload (relative clean and dirty tank level).Active suspension would be provided by electrical actuators orsolenoids, fluid power, or the like, with appropriate damping and springresistance, as understood by those of ordinary skill in the art.

The center of gravity of the robot will tend to move during recovery offluids unless the cleaner and waste tanks are balanced to continuallymaintain the same center of gravity location. If a fluid recovery systemthat is capable of recovering nearly all of the fluid put downregardless of the surface, or modeling predicts how much fluid will berecovered into the waste tank, maintaining the same center of gravitylocation (by tank compartment design) can allow a passive suspensionsystem to deliver the maximum available traction. The present inventioncontemplates a tank design that includes a first compartment having aprofile that substantially maintains the position of the compartmentcenter of gravity as it empties, and a second compartment having aprofile that substantially maintains the position of the compartmentcenter of gravity as it fills, wherein the center of gravity of thecombined tanks is maintained substantially within the wheel diameter andover the wheels. This is more readily achieved with tanks that are atleast partially stacked in the vertical direction.

While the cleaning tanks as configured are integral, the inventioncontemplates the use of cleaning fluid cartridges. The user would inserta sealed plastic cartridge into a depression or cavity on the robothousing, the cartridge smoothly or substantially smoothly (perhapsslightly raised) completing the top and/or side outer profile of therobot, and preferably being configured to contain a pre-measured amountof cleaning fluid. Securing the cartridge into the robot would pierce orcrack the cartridge housing, allowing the cleaning fluid to mix with thewater in the correct amount.

As noted above, absent perfect fluid recovery or active suspension,superior mobility can be achieved either by modeling or assuming aminimum percentage of fluid recovered across all surfaces (70% of fluidput down, for example) and designing the profile of the compartments andcenter of gravity positions according to this assumption/model. In thealternative, or in addition, setting spring force equal to the maximumunladen (empty tank) condition can contribute to superior traction andmobility. As a rule, suspension travel should at least equal the maximumobstacle allowed by the bumper (and other edge barriers) to travel underthe robot.

Maximizing the diameter of wheel decreases the energy and tractionrequirements for a given obstacle or depression. Maximum designedobstacle climbing capability should be about 10% of wheel diameter orless. A 4.5 mm obstacle or depression should be overcome by a 45 mmdiameter wheel. In most embodiments described herein, the robot is shortand squat for several reasons. The bumper is set low to distinguishbetween carpet, thresholds and hard floors, such that a bumper about 3mm from the ground will prevent the robot from mounting most carpets(about 2-5 mm bumper ground clearance). The remainder of the robotworking surface, e.g., the dry vacuum and wet cleaning head under therobot, also have members extending toward the floor (air guides,squeegees, brushes) that are made more effective by a lower groundclearance. Because the ground clearance of one embodiment is between 3-6mm, the wheels need only be 30 mm-60 mm. However, larger is typicallybetter, even when lower obstacles are addressed.

As shown in the various FIGS., at the bottom of the front bumper 220 arecrenellations, in this case thin lateral tabs set at intervals along thelength of the front bumper. These tabs act as a mechanical carpetdetector subsidiary to the main collision or obstacle detection ofbumper 220, being members protruding toward a height at which carpetwould pass under the robot before the front wheel climbs the carpet, setat about 3 mm from the floor about the lower periphery of the frontbumper, and capable of actuating the front bumper. The tabs extend belowthe front edge of the front bumper. In addition, inner cover 200 a ofthe robot, necessary to shield the interior of the robot when the tankassembly is removed, provides additional stiffness, reducing therequirements on the chassis 200 (lower part 200 b).

Robot Controller (Circuit) and Control

In accordance with at least one embodiment, the robot may include agenerally circular or round chassis 200 (see FIG. 3, for one example),to which at least first and second drive wheels 1100 may be rotatablyconnected. The drive wheels 1100 may be positioned on a bottom portionof the chassis 200, so as to bear the robot across the cleaning surfacewhen the drive wheels 1100 are driven. Further, the drive wheels 1100may be positioned such that the respective centers of each drive wheel1100 lie along a virtual line that is generally parallel to the plane ofthe cleaning surface, for example. Various control sequences for therobot of the present invention and its components are described herein.Additionally, the robot may navigate through a working environment usingvarious control and navigational systems known in the art, including,but not limited to those disclosed in U.S. application Ser. Nos.11/176,048, 10/453,202, and 11/166,986; U.S. Provisional ApplicationSer. No. 60/741,442, filed on Dec. 2, 2005, entitled “Robot Networking,Theming, and Communication System,” by Campbell et al.; and U.S. Pat.No. 6,594,844; the entire disclosures of which are herein incorporatedby reference in their entireties

In one embodiment, the virtual line may extend through a center point ofthe circular chassis 200 of the robot, and the drive wheels 1100—whichinclude a left drive wheel and a right drive wheel—may each bepositioned at a mutually opposite outer edge of the chassis 200. Thedrive wheels 1100 may then be driven simultaneously in aforward-spinning direction so as to propel the robot over the cleaningsurface; also, the drive wheels may be driven differentially, with oneof the drive wheels 100 being driven to spin more rapidly than theother, such that the yaw of the chassis 200 rotates about its centerpoint. As a result, the robot can maneuver even where there is noheadroom, because the differentially driven drive wheels 1100 can rotatethe chassis 200 of the robot without having to simultaneously propel therobot forward or backward with respect to the cleaning surface (this maybe accomplished by driving each drive wheel 1100 at the same rate ofspin, but in mutually opposite directions, for example).

In accordance with another embodiment, the robot chassis 200 may includea scrubbing module 600 (see FIG. 12A, for example), which has agenerally linear shape and which may extend from a first point along anouter circumferential edge of the circular chassis 200, through thecenter point, and to a second point along the outer circumferential edgeof the circular chassis 200 (thereby generally defining a centralbisecting line through the center of the circular chassis 200, forexample). In such an embodiment, both drive wheels 1100 are positionedon the bottom portion of the chassis 200 on either the fore or the aftside of the scrubbing module 600, and in certain embodiments, to the aftof the scrubbing module 600 so as to contribute to the navigationalstability of the robot, for example. Other drive wheel locations arepossible. As one example, a robot having 4 drive wheels, one forward andaft of the cleaning head on either side of the robot, and with 3 drivewheels—on the right side one forward and one aft of the cleaning head,and on the left the wheel positioned on the diameter to the left of thecleaning head. Such configurations could give the robot movement moresimilar to a robot having differential drive on the center line, andfacilitate software optimizations for controlling movement of the robot,among other things.

In accordance with one embodiment, the mobile robot 100 may clean afloor or other cleaning surface using a generally spiral path, forexample. By choosing a spiral path in accordance with an effective widthof the liquid applicator 700, for example, the robot can effectivelydeposit cleaning fluid over a maximal area of the cleaning surface. Insuch a case, a robot with a dominant side turns away from the dominantside, in order to have the dominant side (i.e. a side upon which thecleaning head extends to the edge, and upon which the robot followsobstacles) form the outside of the spiral. For a simple spiral, this canleave a spot that is uncleaned, e.g., where the cleaning head is offsetto the right and the robot spirals to the left, the robot-bottom portionwith no cleaning head coverage creates a small uncleaned circle in thecenter of the spiral (although this circle is temporary given that therobot will probably return randomly to the same spot before the end ofthe cleaning cycle). This can be addressed by following the spiral witha center pass based on dead reckoning, or by following the spiral withone or two figure-eights based on dead reckoning. However, in the casewhere the robot encounters a wall or obstacle before the spiralingmethod is to initiate the center pass, there remains some probabilitythat this interruption will leave the uncleaned circle (reversing thedirection of the spiral from the obstacle or arbitrarily may be used toreach the circle spot as well).

As an alternative coverage pattern which does not necessarily createsuch spot is shown in FIG. 46. In such a pattern the mobile robot 100may follow an overlapping pattern similar to that used by iceresurfacing machines used on skating rinks, in order to ensure that allthe areas within the path are properly covered. FIG. 46 shows thegeneral wheel path in dotted lines 911, and the general coverage path insolid lines 913. The pattern is most simply a series of circles or ovalsthat overlap one another, with the diameter of the path followed beinglarger than the width of the coverage track. It may be implemented as aseries of overlapping rounded-corner squares or rectangles, rectanglesshown in FIG. 46. As shown in FIG. 46, an exemplary pattern usesessentially right-angle differentially steered turns. The robot travelsa distance away from a first track, turns parallel to it, travelsparallel to it, then turns back to the first track, eventually turningbefore the first track to overlap it and drive parallel along the firsttrack. The overlap is sufficient to cover any “blank spots” caused bythe offset cleaning head or offset differential wheels. The robot thenturns at essentially a similar position to the first turn, and repeatsthis process treating the track just made as the first track.Successively, although the robot leaves a blank, uncleaned area in themiddle at the initiation of the coverage pattern, the robot will shiftthe overlapping oval, circle, square, or rectangle such that the blankarea is eventually covered. As can be seen in FIG. 46, the diameter ofor distance across the first loop and subsequent loops of the patterncan be any size, as the robot will overlap the coverage eventually.Larger loops also have greater cleaning efficiency if they incorporatemany straight lines. However, if the loops are too large, drift erroraccumulates, obstacles may be encountered disrupting the pattern, etc.If the loops are too small, then too much time is spent in differentialturns, during which cleaning is not as satisfactory as straightcruising, and which is slower than straight cruising as well. In thepresent case, the coverage pattern described above is of a size thatwill completely cover the center of the loop on the third to fifthparallel pass (parallel whether the loop shape is irregular, circular,oval, square, or rectangular), and overlaps by no more than half of thecleaning width on each pass. One exemplary tight coverage patternoverlaps by about 120%-200% of the straight line distance from the wheelcenter to the cleaning head edge (or in the alternative has loops offsetby the cleaning width minus about 120%-200% of this distance, oralternatively simply overlaps by about ⅕-⅓ of cleaning head width, oralternatively has loops offset by about ⅔-⅘ of cleaning head width), andhas loops that are less than about three or four times the workingdiameter. These loops are substantially symmetrical, either circles,polygons, squares (the latter two with curved corners as the robotturns).

FIG. 48 illustrates a mobile robot having left and right drive wheels1100 positioned on the aft bottom portion of the chassis 200, in which adotted line indicates the virtual line extending through the centers ofboth drive wheels 1100. Because the virtual line of the“diameter-offset” robot does not pass through the center point of thechassis 200 (which is different from the on-diameter robot shown in FIG.47, for example), however, the differential yaw control effected bydifferentially driving the left and right drive wheels 1100 is differentfrom the embodiments in which the virtual line passes through the centerpoint of the chassis 200. For example, in contrast to the centerpoint-intersecting example, the robot illustrated in FIG. 49 necessarilyundergoes simultaneous forward or backward motion by the robot withrespect to the cleaning surface, when the yaw of the robot is altered bydifferentially driving the drive wheels 1100. Accordingly, the controlof the diameter-offset robot (herein “offset robot”) for various taskssuch as sharp turning, proceeding along curved paths, cliff-following,bump-follow behaviors or other such behaviors is altered from thenon-diameter-offset robot, taking into account the differences caused bythe offset of the drive wheels 1100 from the diameter (i.e., thecentrally bisecting virtual line) of the chassis 200. Several exemplaryoffset robot behaviors, which the robot's controller can implement tocontrol the robot accordingly, are discussed below.

The robot may include a bump follow behavior. The bump follow behaviorfacilitates the escape of the offset robot from a narrow or partiallyenclosed area (such as an alcove or narrow end of a hallway, forexample). The bump follow behavior may include at least two phases: (1)Turning in place (i.e., adjusting the yaw of the robot) when a bumper(or other suitable contact or pressure sensor for detecting contact ofthe robot with an obstacle, such as a leaf-spring switch, magneticproximity switch, or the like) is compressed, and (2) moving in agenerally arc-shaped path in the opposite direction of the turn with adecreasing radius until the bumper is compressed again.

In accordance with at least one exemplary implementation, phase 1 of thealgorithm modifies the radius of turn to keep the bumper against thewall while turning (see FIG. 49). L1 is a virtual line that extendsthrough the centers of the drive wheels 1100, and the robot can rotateabout any point on this line. L2 is a virtual line that is perpendicularto the wall and passes through the center of the robot (point C). PointA is the intersection of L1 and L2. In accordance with this algorithm,for example, the robot may maintain a constant distance ‘d’ between therobot and the wall.

To turn the robot while keeping ‘d’ constant, the robot adjusts therespective wheel velocities for the first and second drive wheels 1100such that the robot rotates about point A. This can be a continuousprocess such that point A moves with respect to the cleaning surface, asthe robot rotates.

Referring to FIG. 50, for example, the controller implements analgorithm based on control cycles in order to effect the properbehavior. At an initial step S101, the robot waits for a control cycle,after which the robot recalculates the estimated position of point A atstep S102. Subsequently, the robot sets the respective spinning speedfor each drive wheel 1100 at step S103, in accordance with therecalculated position of A; then, the process repeats at the first stepS101.

In accordance with embodiments in which the robot may not have a sensorthat indicates what angle the wall is relative to the robot, the controlalgorithm may estimate the position of point A based on which bumperswitch is closed (left, right, or both) and may update its estimate asthe bumper switch closure state changes. Accordingly, this estimationmay allow the bump follow escape behavior to work well most of the time.

With reference to FIGS. 51 and 52, an exemplary estimation process isillustrated, in which the term ‘bump quadrant’ refers to which bumpswitches are closed—‘left’ means only the left switch is closed, ‘right’means only the right switch, and ‘both’ means that both the left andright switches are closed. FIG. 51 illustrates an example of acontinuous algorithm that updates the wall angle every control cycle,and FIG. 52 illustrates how the estimate is updated when the wallquadrant changes.

For example, as illustrated in FIG. 51, at an initial step S201, therobot forms an initial estimate of the wall angle based on the bumpquadrant, then waits for a subsequent control cycle at S202. Once thecontrol cycle begins, the robot determines at S203 whether thecurrently-detected bump quadrant is different from the previous bumpquadrant, and if so, reestimates the wall angle based on the previousbump quadrant and the current bump quadrant at S205, and returns to S202to wait for a subsequent control cycle (thereby forming a process loop).If, however, the current and previous bump quadrants are the same, therobot estimates at S204 the wall angle based on wheel movements duringthe control cycle instead of differences in bump quadrants, and thenreturns to the control cycle waiting step S202, as well.

As shown in FIG. 52, the process proceeds along a first series of linkedtest steps (S301, S307, S312, S317 and S319), including determiningwhether the previous bump quadrant was left, both, or right; or, whetherthe current quadrant is left or right. If none of the determinations inthis initial series of linked test steps are ‘yes,’ then the robotreaches a default estimation for the wall angle of 0 degrees at S321.However, if on the other hand the robot determines that the previousbump quadrant was left, then the robot next determines at S302 whetherthe current bump quadrant is both (in which case, the robot estimatesthe wall angle as 7.5 degrees at S305), at S303 whether the current bumpquadrant is right (in which case, the robot estimates the wall angle as0 degrees at S306), or otherwise, defaults the estimate to 0 degrees atS304. If, on the other hand, the previous bump quadrant was instead bothas determined at S307, then the process estimates the wall angle as 7.5degrees at S310 if the current bump quadrant is determined as left atS308, or −7.5 degrees at S311 if the current bump quadrant is right asdetermined at S309; otherwise, the wall angle estimate defaults to 0degrees at S304. Furthermore, if the previous bump quadrant was right asdetermined at S312, then the robot estimates the wall angle as −7.5degrees at S315 only if the current bump quadrant is both as determinedat S313; otherwise, the estimate defaults to 0 degrees (via S316, ifS314 determines the bump quadrant as left, or via S304 otherwise).

On the other hand, if the previous bump quadrant was not left, right, orboth—such as may occur on an initial control cycle when no previous bumpquadrant has yet been detected—then the robot determines at S317 whetherthe current bump quadrant is left (in which case the estimate becomes 30degrees at S318) or right, as determined at S319 (in which case theestimate becomes −30 degrees at S320); otherwise, the estimate for thewall angle defaults to 0 degrees at S321.

The robot may also have cliff avoidance and panic spin behaviors. Inaddition, the robot may use a direction lock algorithm in order to getout of corners and distribute itself throughout a room or other areacontaining the cleaning surface. This may occasionally result in therobot turning into an obstacle or cliff it just detected. Thus, in orderto avoid dropping off a cliff in a situation in which the offset robotturns toward an obstacle or cliff it has just detected in accordancewith the direction lock algorithm (which might occur because the offsetrobot does not rotate about its center without accompanying forward orreverse translational movement with respect to the cleaning surface),the offset robot may back up a further distance (for example, about 10mm, although distances from about 5 mm up to about twice the diameteroffset may alternatively be used). Backing up too far could lead tofalling off a different cliff which might lie behind the robot, becausethe robot might not have cliff sensors on the rear of the robot in someembodiments. Further, the robot may also turn a further amount (for anon-limiting example, 20 degrees; or, any angle within 0 through 90degrees also being suitable, alternatively) when turning towards adetected cliff, compared to a non-offset robot.

FIG. 53 illustrates an exemplary algorithm that an offset robot mayemploy. At an initial step S401, the robot determines a direction of adetected cliff, based on which cliff sensor among at least a right cliffsensor and a left cliff sensor (as non-limiting examples) aretriggered—if only the right cliff sensor is triggered, the robotdetermines the cliff is to the right; if only the left cliff sensor istriggered, then the robot determines that the cliff is to the left;otherwise, the robot instead determines a direction at random. Next, therobot determines at S402 whether the direction is locked, and whether itis different from the direction of the cliff. If yes, at S403 the robotbacks up (for example, by a particular distance, such as 10 mm;alternatively, the distance may be dynamically set in response to otherenvironmental or behavioral factors known to the robot, or by anysuitable predetermined amount) and turns (for example, by a particularamount such as 20 degrees; alternatively, the turning amount may bedynamically set, or may be any suitable amount) before again proceedingforward. Otherwise, at S404 the robot then proceeds according to theusual cliff avoidance behavior.

The panic spin behavior is used to escape when robot determines that itmay be stuck on an obstruction. In embodiments in which the robot is anoffset robot, and is unable to rotate in place about its center withoutnecessarily simultaneously moving forward or backward, and thus placethe offset robot in danger of going over a cliff, the offset robot mayreverse its panic spin direction if it encounters a cliff during thebehavior.

As shown in FIG. 54, for example, in accordance with one example of apanic spin behavior for an offset robot, the robot may randomly choose arotational direction and magnitude in which to turn about its center, ata first step S501. The robot then may begin its spin at S502, and thenwait for the next control cycle at S503. Subsequently, the robot may setits speed based on the chosen turn angle at S504, and then test whetheror not a cliff has been detected at S505. If so, the robot then reversesits spin direction at S506, and the control process then loops back toS503 to wait for a subsequent control cycle; otherwise, the controlprocess simply loops back to S503 to wait for the subsequent controlcycle, without reversing the spin direction.

The robot may have a bounce behavior for handling low traction. Therobot may operate in environments in which the floor or other cleaningsurface is wet, and there may be other elements or protrusions on thebottom of the robot chassis that may contact the floor and reduce wheelcontact force. To handle this, when the bumper is triggered, the bouncebehavior for the robot may generally back up at least about 10 mm (orany other suitable distance), and then stop backing up when it haseither backed up a further 20 mm (or other suitable distance) or thebumper has released. In contrast to conventional robots, a robot inaccordance with this embodiment may back up a minimum amount beforescanning to determine whether the bumper is released. The total distancemay also be kept to a minimum to avoid inadvertently backing off acliff, but enough that the robot can turn.

The robot may also include a wheel drop behavior for detecting floortransitions and drops, as well as gradually sloping obstacles or objectswhich might not otherwise be detected by bumpers or other obstacledetection sensors. For example, if the front of the robot rides up on ashallow transition in the floor, or when the front of the robot islifted by a gradual rise or object on the cleaning surface that does notalert the robot to its presence by triggering a bumper or other sensor,the front wheels 1100 of the robot may drop down and thus lose contactwith the surface. Accordingly, the robot may include a sensor whichtriggers when the wheel of the robot drops to its lowest position (orany other lower-than-normal point suitable to indicate a likely loss ofcontact). Thus, when the front wheel drops, the robot may then react toa triggering of the wheel drop sensor in a manner similar to a bumperhit. As a non-limiting example, if, after backing a short distance, thewheel does not return (for example, the wheel drop sensor fails to ceaseto trigger), the robot may then stop (and, for example, alert the userwith a wheel drop error code, alarm, or other indication) for safetyreasons. By reacting to a wheel drop condition as a bump, for example,the robot may avoid going up onto carpets or other undesired floorsurfaces or obstacles.

FIG. 55 shows that upon entering the wheel drop behavior, as a firststep S601, the robot moves in reverse at S602 until at S603 the robothas reached a particular distance (for example, 50 mm), or a particularamount of time has passed (for example, 1 second, or any other suitableamount of time), and/or the wheel drop sensor no longer is triggered(for example, if the wheel drop sensor is a continuous-type sensorrather than a pulse-type or momentary-type sensor). Subsequently, therobot determines at S604 whether the wheel drop sensor no longer istriggered, and if so, the robot may then enter the bounce behavior modeand/or continue to clean the cleaning surface (alternatively, forexample, the robot may simply revert to its normal mode, or any othersuitable behavioral mode) at S605. If, on the other hand, the wheel dropsensor has not ceased to trigger, the robot may then cease its cleaningbehavior (or traveling behavior, as may be the case), and may also issuean alarm, error code, or other “distress” indicator in order to alertthe user that the robot is no longer cleaning and has entered astationary “fail safe” mode at S606, as a non-limiting example.

Certain embodiments of the wet cleaning behaviors are described below.In accordance with some embodiments, in which the robot includescomponents for wet cleaning of the cleaning surface (by including theliquid applicator module 700 and associated elements), the vacuum fanmotor may be operating the entire time the robot is cleaning. As aresult, any liquid previously deposited on the cleaning surface—forexample, cleaning liquid left over from a previous cleaning cycle, orliquid from a beverage spilled on the floor by a person, or any otherliquid—may be removed from the cleaning surface; in addition, any liquidor moisture which remains within the robot or on robot components (forexample, as a result of wet cleaning operations performed by the robot)may more quickly dry out as a result of air flow drawn over the residualliquid or moisture. Thus the robot may become properly dry more quickly,and the likelihood of undesirable leaking or spilling of liquid from therobot, such as may occur when a still-wet robot is prematurely handledby a user, may be reduced. Further, the brush and pump may be controlledin accordance with the cleaning and mobility characteristics of therobot. Additional robot behaviors related to wet cleaning robots aredescribed below.

The robot drying process may be triggered, for example, by one or moreconditions such as, for example, a timer that causes the robot toinitiate the drying process at a particular time of day, or after anelapsed period of time during a wet cleaning cycle; or, as in thealternative, in response to a sharp drop off in battery voltage suppliedto the robot, which may indicate that the battery will soon not providesufficient power. As an advantage, for example, the robot may beconfigured to ensure that it is dry before the power supply from thebattery is completely drained.

Embodiments of the main brush control are described below. When therobot is in motion, the main brush may spin in a clockwise directionwhen viewed from the right hand side of the robot, as illustrated inFIG. 3, for example. As a result, forward force is contributed to therobot as the clockwise-spinning main brush contacts the cleaning surfaceor floor, for example, facilitating forward propulsion of the robot withrespect to the cleaning surface. Likewise, when backing up, the robotmay turn the brush off; and the robot may also leave the brush turnedoff until it has traveled forward at least, for example, about 25 mm (analternative suitable distance or time delay may be used, for example,about 0-50 mm) upon resuming forward movement. Alternatively, when thebrush can be caused to rotate in a reverse direction (e.g., in acounterclockwise direction, when viewed from the right hand side of therobot) when the robot backs up, in order to provide additional reversepropulsive force, as a non-limiting example.

FIG. 56 illustrates an exemplary brush control process in accordancewith such an embodiment. The robot may wait for a next control cycle atS701 (herein referred to as the “first step,” although the behavioralcontrol process may alternatively begin at any suitable point, forexample, and is not limited to beginning at this step), and thendetermines whether or not the robot is backing up at S702. If not, thenthe robot turns on the brush (or leaves the brush on) at S703, thenreturns to the first step S701.

On the other hand, if the robot is determined to be backing up, therobot may then turn off its brush at S704, then wait for a next controlcycle at S705; upon the next control cycle, the robot may againdetermine whether the robot is backing up at S706, and if so, theprocess may sub-loop by returning to the immediately preceding waitingstep S705 and wait again for a next control cycle. However, if the robotdetermines that the robot is not backing up at this sub-loop, it maythen proceed out of the sub-loop and set a distance counter to aninitial state (such as setting an integer value stored in electronicmemory to zero, or a count register, or mechanical counter, or othersuitable counter, as examples) at S707, and then enter another sub-loopby waiting again for a next control cycle at S708. Upon the next controlcycle, the robot may then increment (or decrement) the distance counterat S709, and then determine whether the distance counter has reached orexceeded a threshold value (e.g., 25 mm, or 1 second, or any othersuitable threshold) at S710.

If the robot determines that the distance counter has not reached orexceeded the threshold value, the robot may reiterate this sub-loop byreturning the process to the immediately preceding next-control-cyclewaiting step at S708, for example. Otherwise, the robot may instead thenturn on (or leave on) the brush at S703, and return to the first stepS701 in the brush control process.

For embodiments of robots which include wet cleaning capability, a pumpmay be included which can be controlled to dispense cleaning fluid ontothe cleaning surface, for example. In order to effectively distributecleaning fluid on the floor, the robot may control the output shaft ofthe pump to a specific rotational speed, including embodiments in whichno mechanical speed sensor is included. Also, the robot may turn thepump off under various circumstances while cleaning to avoid putting toomuch fluid down in one spot, such as, for example, when the robot is nottraversing the cleaning surface at an appropriate rate to appropriatelydisperse the cleaning fluid. In addition, the robot may perform aspecific sequence at startup to prime the pump quickly. Further, thepump may be turned off for 5 minutes after cleaning is complete, toproperly dry the inside of the robot, although this may be from about 15seconds-15 minutes depending on the air flow and fluid properties. Otherexamples of pump control and pump-related behaviors are described below.

In one embodiment, the robot may ascertain the floor area of a room tobe cleaned, either by initially traversing and recording the boundariesof the room, or by receiving information from a user or computer.Thereafter, the robot may control the pump in proportion to theascertained size of the room, in order to ensure that the entire floor(or at least a maximal or optimal area thereof) receives an effectiveamount of cleaning fluid, for example. As an advantage, cleaning fluidcan be conserved and the risk of leaving the floor only partiallycleaned may be reduced.

In at least one embodiment, a robot may include a pump which is areciprocating diaphragm pump having two chambers. The pump is driven bya small DC motor, and the output shaft has an eccentric cam that drivesthe pump mechanism. The output speed of the pump may be controlled to aparticular rotational speed to distribute the correct amount of cleaningfluid. To avoid the cost and potential unreliability of a mechanicalsensor, an electrical sensor may be included, as well. When driven witha substantially constant voltage, for example, the current drawn by thepump may be represented by a signal having a period that varies with theoutput speed of the pump, as illustrated in a non-limiting example inFIG. 57. By measuring the current of the pump over time and analyzingthe resulting data, the speed at which the pump is turning can bedetermined.

As noted herein, the diaphragm pump distributes water in front of thecleaning head. A single membrane sandwiched between two housing piecesacts as both inlet and outlet check valves and pumping chamber. The pumphas two independent circuits which supply two outlet nozzles. The pumpis actuated by a cam such that the nozzle output is constant per unitdistance squirted. In other words, the cam drives the pump so eachnozzle leaves a uniform puddle across the full width of the cleaningbrush. The output of each pump channel is directed to nozzles which arepositioned directly opposite each other in line with each end of thecleaning brush and in front of the cleaning head. The nozzles squirtwater parallel to and in front of the cleaning head. They squirtdirectly out of phase at the same frequency in an effort to minimize thelinear travel distance between output puddles. The reason for twonozzles is to reduce or eliminate any unevenness or inaccuracy apparentin a single nozzle. By having two opposing nozzles, the outputs areaveraged, and the cleaning fluid is applied uniformly.

In accordance with at least one embodiment, the robot may analyze datapertaining to the pump speed using a pseudo-autocorrelation algorithm orother suitable algorithm. The current that the pump is drawing may besampled every control cycle (generally about 67 times per second, orother suitable rate, e.g., from 10-200 times per second) and put into abuffer. The buffer analyzes every control cycle (or other suitableperiodic rate) to estimate the period of the signal. Thepseudo-autocorrelation algorithm outputs a correlation value for a rangeof sample periods, from about 194 ms (corresponding to 79 RPM), forexample, to about 761 ms (309 RPM) at 15 ms intervals, in accordancewith one example (noting that the particular values of time, interval,and rate are simply non-limiting examples, which may be substituted withany other suitable values). A correlation value is calculated by summingthe absolute value of the difference of a number of samples in thebuffer separated by the sample period. A lower correlation valuegenerally indicates a better match.

The pseudo autocorrelation algorithm may sometimes falsely indicate amatch even for incorrect frequencies, because it can match onfrequencies whose period is a multiple of the correct period, and if thetwo lobes of the signal are similar in size it may also falsely indicatea match on half the period. To help avoid this problem, an estimate ofpump speed may be calculated from the voltage being supplied to the pumpand the current being drawn. In accordance with an exemplary embodiment,this may be based on data measured from several sensors to measure theappropriate constants. In accordance with this process, examples offormulas for determining an estimated pump RPM based on voltage andcurrent readings may include, among others:Period_from_voltage=61−2.5*V;Nominal_current=8.4+3.95*V;Slope=1.3302−0.07502*V;Period=Period_from_voltage+(I−Nominal_current)*Slope; andRPM=4020/Period.

Although all of which should be considered to be alternatively +/−5percent, or up to +/−20 percent, the values have been determinedempirically to take into account tolerance variation among pumps andmotors.

FIG. 58 illustrates one example of an algorithm used to determine thepump speed. At an initial step S801, the robot calculates a correlationvalue for each period, then at S802 find the two smallest correlationvalues which are greater than 50 below the average value. This is anempirically determined constant and is a non-limiting example.Reasonable values will vary widely depending on actual pump currentvalues, how pump current values are converted to digital values, and thesampling rate. Then, the robot determines whether or not there are novalid correlations at S803—if there are none, the process determinesthat the period is unknown at S804; on the other hand, if thedetermination is not that there are no valid correlations, the processthen determines whether or not there is only one correlation at S805. Ifso, the process returns the period of the one valid correlation at S806.Otherwise, the process the determines at S807 whether or not twocorrelations have periods of three or fewer peaks and if so, then theprocess returns the period of the smaller correlation at S808.

If not, the process determines at S809 whether the smallest correlationhas a value that is smaller by more than 25, in which case the processreturns the period of the smaller correlation at S810. Just as above,this is an empirically determined constant and is intended only as anexample. Otherwise, the process then determines whether the periods are1.5×, 2×, or 3× multiples at S811. If not, the process determines theperiod as unknown at S812; otherwise, the process proceeds to calculatean estimate of the period (the estimate is calculated as describedabove) at S813, and then determines at S814 whether or not the estimatethus produced is substantially closer to one of the periods—and, if so,the process returns the period closer to the estimate at S815; if not,the process returns the smaller period at S816.

The robot may include pump disable control as well. In some embodiments,the pump may be stopped in various circumstances to avoid putting wateron the floor where the robot will not (or is unable to) pick it up. Forexample, if the pump were to run (and thus cause cleaning fluid to bedeposited) while the robot was backing up, the water that was put downmight not get picked up because the part of the robot that picks upfluid is behind the fluid outputs (unless the robot were to re-traversethe area it backed away from).

Conditions in which the pump may be stopped may include, inter alia: (1)when the robot is moving backwards; (2) when the robot is turning inplace (for non-offset robot embodiments, or, alternatively, when therobot is turning in a very small area, such as for either offset ornon-offset robot embodiments); (3) when the robot is turning about apoint closer to the center of rotation than half the wheel spacing;and/or (4) when the robot detects circumstances that are interpreted asa stuck condition.

FIG. 59 depicts an example of a sequence for implementing a stuckbehavior for a wet cleaning robot. At a first step S901 (noting thatalthough this is referred to as the “first step” for explanatoryconvenience, the process may alternatively begin at any other suitablestep in the process) the process sets a “may be stuck” variable or flag(which may be a location in an electronic memory, or a flip-flop, ormechanical switch, or any other suitable structure; herein referred toas “maybe stuck”) to a-state representing “not stuck” (herein referredto as “false”; the opposite state referred to as “true”). The processthen waits for a next control cycle at S902, and then determines whetherthe robot is in a constant bumper panic state (for example, a state inwhich the bumper triggers continuously) at S903, and, if so, the processsets maybe stuck to true at S904, waits for the bumper to be cleared fortwo seconds (e.g., 0.2 to 10 seconds) at S905, and then reiterates thestuck behavior process by returning to the first step S901. Otherwise,the process determines at S906 whether any other panic states exist; ifso, the process sets maybe stuck to true at S907, waits for the bumper,cliff sensor, and/or virtual wall sensor to activate at S908, and thenreturns to the first step S901. If not, the process determines at S909whether the wheel drop sensor is triggered; if so, the process setsmaybe_stuck to true at S910, waits for the wheel drop sensor to be clearfor two seconds (e.g., 0.2 to 10 seconds) at S911, and then returns tothe first step. Otherwise, the process sub-loops by returning to S902 towait for the next control cycle.

The robot's pump may also require a priming sequence. In embodiments ofrobots which include a pump, the pump may be run at full voltage for (asa non-limiting example) 2 seconds (or any other suitable interval) atstartup, to facilitate priming of the pump.

A drying cycle may also be included in certain embodiments of thecleaning robot. For example, wet cleaning robots may generallycontinuously vacuum up dirty cleaning fluid (and/or other liquid) fromthe floor or cleaning surface. The fluid may form a residue along vacuumchannels inside the robot. To avoid leakage of the fluid or residue fromthe robot (which leakage may form a puddle or streak on the cleaningsurface) following a cleaning cycle, the robot may run for a period oftime (herein referred to as “the drying period”) after cleaning isstopped, with the pump turned off and the vacuum running. During thedrying period, the vacuum may be maintained on and/or the brush may bekept spinning, to dry the brush and its enclosure. The robot may alsomove within its environment (for example, in its normal cleaningpattern), to allow the robot to pick up any liquid remaining under therobot that may continue to be pushed around with the robot's squeegee,as well as to avoid potential damage to the floor or cleaning surfacethat may be caused by spinning the brush in one place.

The robot has additional sensors. In accordance with at least oneembodiment, a wet cleaning robot may include one or more sensors suchas, for example, a fluid level sensor, a Filter, Cleaning Head, and/orTank Present Sensor, inter alia. A robot may include, as a non-limitingexample, two fluid level sensors—one to sense if there is any cleanfluid remaining, and another to sense if the waste fluid tank is full.Each sensor may use the same electronics and driving processes. FIG. 60illustrates an example electronic circuit, in which R1 and R2 arecurrent limiting resistors (which may have the same value, or,alternatively, differing values).

To get a reading from the sensor, the control process may set Output 1to +5V, Output 2 to 0V, and read the analog input (Reading 1). It maythen reverse the outputs, setting Output 1 to 0V and Output 2 to +5V(other voltage values +3.3, 12, 24 would be suitable for other systemvoltages). Then, the process may read the analog input again (Reading2), and subtract the two readings (i.e., subtracting Reading 2 fromReading 1) to obtain, as a result, the voltage across the senseelectrodes, herein called the “Sense Voltage.” Accordingly, a set offormulas may be used to calculate the resistance across the senseelectrodes, such as, for example:Voltage across R1 (or R2)=(5 V [from the voltage applied to the pinabove]−Sense Voltage)/2;Current across R1 (or R2)=(Voltage across R1)/R1; and/orSense Resistance=(Sense Voltage)/(Current Across R1).

Generally, these formulas are effective if R1 and R2 are the same, anddifferent formulas would be required if R1 and R2 are different. Whenthe Sense Resistance is below a threshold, the sensor indicates fluid isbridging the electrodes. As an example, R1 and R2 may be 2K ohms(optionally 300 to 5000 ohms), and the threshold may be 30K ohms (or,alternatively, any other suitable values, e.g., 5K to 80K ohms).

The robot may also include filter, cleaning head, and tank sensors. Eachof these components (Filter, Cleaning Head Assembly, and Tank Assembly)may include a magnet. In a corresponding position in the robot, theremay be a reed switch that closes in the presence of a sufficientlystrong magnetic field (alternatively, a relay-type switch, pressuresensor, optical sensor, or any other appropriate system for detectingthe presence of the above-noted components may be used). This allows thecontrol system to check if these components are properly installed. Asthe filter may be of critical importance, because the vacuum fan wouldbe very easily damaged by foreign material, and because without thecleaning head assembly or the tank, the robot would not clean the floor,the control system may not allow the robot to run if any of thesecomponents are missing or go missing during the run, in accordance withat least one embodiment.

To avoid falsely preventing the robot from running when the tank isactually present but the sensor has failed, the control system may allowthe robot to clean if the tank present sensor is not working. Inaccordance with one example, if the tank present sensor was working atthe start of the run, and the tank present sensor indicates the tank isremoved during the run, the robot may stop.

The user interface for the robot may consist of simply a power button.However, additionally, a cleaning button may be provided. In oneexample, each of the power button is provided with a light.

As shown in FIG. 62, in order to provide the user with informationregarding the robot's operation, the power button may be used to signifybattery charging status, e.g., red for empty, pulsing green for charging(fast or slow for different charging cycles or battery refresh cycle),solid green for fully charged, blinking red for not installed. The cleanbutton may be used to signify cleaning tank status or cleaning operationstatus, e.g., green for cleaning, blue pulse for drying (clean nearlycompleted), solid blue tank is empty clean cycles is complete.

Accordingly, in this user interface example, the robot has a battery anda replenishable material tank, and a panel is provided with twoilluminable buttons, one of the buttons controlling an on/off or poweroperation of the robot and being illuminated, optionally in patternsand/or colors, according to the on/off or power status; and the otherbutton initiating a cleaning operation by the robot using thereplenishable material tank and being illuminated, optionally inpatterns and/or colors, according to the status of the replenishablematerial in the tank and/or the status of a cleaning cycle and/or dryingcycle using the replenishable material in the tank. “Illuminate”essentially means activate, and forms of rendering a warning morevisible (change color, turn from light to dark, pop up, and the like)without actual illumination are included. An alternative would use onebutton and patterns and/or colors to signify power and/or replenishablematerial status as discussed above. Pressing one or two buttons incombinations (tap, long press, double tap, press both, press one and tapthe other) can be used to initiate operations directly, such as startingdrying immediately, overriding a sensor failure, or providing access totesting or diagnosis modes.

As shown in FIG. 63, additional information can be provided with statuslights that are important for monitoring autonomous operation. In such acase, the status lights may be illuminable text that directly indicate aproblem, along with a color recognized as a warning by most people. Ifthe lights are illuminable text messages, there is no need for the userto refer to a manual to interpret the problem on the robot, yet therobot does not include unnecessary complexity by inclusion of a displaypanel and associated control elements. In the present case, a warninglight that indicates the user should “check tank” should actually usethe words “Check Tank”, and may illuminate in a “warning” color (e.g.,yellow, red, orange) color for a service warning (E.g., the tank ismissing) or in a “non-warning” color (e.g., green, blue, purple, white)for a simple status message (e.g., cleaning cycle is complete). Inaddition or in the alternative, a “Check Brush” and “I'm Stuck” lightare useful in the present context. The check brush message may appearwhen the brush is jammed or improperly installed, e.g., by detectingmotor load. The “I'm Stuck” message should appear as a result of therobot's recognition of a stuck or stasis condition, followingappropriate panic, anti-canyoning, escape and other anti-stasis(sometimes “ballistic” behaviors) have been cycled or exhausted. Onedetection would depend upon stasis of the front wheel while either drivewheel turns. A service code 7-segment display element can provideinformation enabling problems to be diagnosed by the user or bytechnicians.

Accordingly, in this user interface example, the robot has a powereddrive and/or a powered brush and/or and a replenishable material tank,and a panel is provided with warning indicia, capable being illuminated,optionally in patterns and/or colors, according to the status of therobot drive and/or brush and/or replenishable material tank. In certainembodiments, the indicia are actual text messages. Further preferably,the illumination is in warning and non-warning colors according to thecircumstances. The replenishable material tank should be able to conveyboth tank malfunction and tank empty messages. Again, these lights areilluminated optionally in patterns.

Operation and Maintenance

FIGS. 36-41 depict a method for operating and maintaining a cleaningrobot physically configured for such operation and maintenance, and alsoincludes information regarding the stacking/assembly order of the partsof the robot and/or the physical configuration dependency of the robot.FIGS. 37-41 depict readily recognized hand positions, motions, and otherphysical actions, as well as readily recognized orientations, positions,and configurations of a cleaning robot, and the present disclosureincludes all that is readily recognized from these drawings.

According to FIGS. 36-41, an embodiment of the robot is structurallyconfigured to permit a tank to be physically positioned to provideaccess to an internal area (S2), or to permit a cleaning head to bephysically removed from the robot body (S3). As shown in FIGS. 36-41,neither depends upon the other, and the cleaning head and tank releasemay be handled independently. Once the tank is put into a releasedposition (S2), the tank may be unloaded (S4). However, even withoutunloading the tank (S4), the internal area becomes available, and theuser may then access a filter that is made visible and accessible (S12),a vacuum port (grommet) that is made visible and accessible (S14), and abattery that is made visible and accessible (S16). Each of these is moreconvenient if the tank is unloaded (S4), but as the tank does not impedegeneral access to the internal area in the released position, each ofS12, S14, and S16 may be carried out without unloading the tank. Thefilter may be flushed and restored (S20) after being removed. Thebattery may be placed and handled differently, e.g., to be inserted inor to the robot body or tank without tank release, the outer surface ofthe battery substantially conforming to the outer profile of the robotwhen the battery is in place.

Once the tank is unloaded (S4), the dirty tank, if full, may be emptied(S6) and flushed (S18). However, whether the dirty tank is full orempty, the clean tank may nonetheless be filled with cleaning fluid (S8)or water (S10), none of these dependent upon the other. The tank, loadedwith mixed cleaning fluid and water (or as noted herein, premixed and/orcartridge cleaning fluid and/or water alone), the tank is loaded (S22)and then “clicked” in to lock the tank in place (S24). The robot maythen operate autonomously. These operations may be in whole or in partcarried out by a dock or cleaning station of the robot. In such a case,it may be advantageous not to release the tank or unload the tank;rather the fluid areas of the robot, as well as the areas includingcleanable parts such as the filter or vacuum port, may be accessedthrough alternate ports in the compartments of the tank provided for thepurpose of automated evacuation of the tank. The present inventioncontemplates the automated docking and/or evacuation of the tank and/orrobot, and incorporates by reference specific description thereof fromthe documents incorporated by reference herein. In such a case, some orall of the steps of FIG. 36 would be process steps carried out by theprocessor, manipulators, and mechanisms of the dock or evacuationstation in communication with the processor of the robot.

In certain embodiments, the cleaning head release and tank release aremade dependent. In such cases, the release for the cleaning head isinside the robot body, and the tank must be in the released position toaccess the cleaning head, as depicted in the FIGS. When in the down orlatched position, the tank locks the cleaning head in place and preventsaccess to the cleaning head release button. In this configuration, thecleaning head engages the tanks via the vacuum channels that extend fromthe tank through the robot body into the cleaning head (as depicted inthe FIGS.). In such a case, the vertical overlap is beneficial forsealing contact, and pulling the cleaning head sideways against thechannels causes wear; thus, the cleaning head may be designed forrelease only when the tank is released to avoid this wear.

It will also be recognized by those skilled in the art that, while theinvention has been described above in terms of preferred embodiments, itis not limited thereto. Various features and aspects of the abovedescribed invention may be used individually or jointly. Further,although the invention has been described in the context of itsimplementation in a particular environment, and for particularapplications, e.g. residential floor cleaning, those skilled in the artwill recognize that its usefulness is not limited thereto and that thepresent invention can be beneficially utilized in any number ofenvironments and implementations including but not limited to cleaningany substantially horizontal surface. Accordingly, the claims set forthbelow should be construed in view of the full breadth and spirit of theinvention as disclosed herein.

1. A surface treatment robot comprising: a robot body having forward andrear ends; a differential drive system mounted on the robot body andconfigured to maneuver the robot over a cleaning surface; a controllerin communication with the drive motor and configured to differentiallysteer the robot and be capable of maneuvering the robot to pivot inplace; a proximity sensor responsive to a potential obstacle forward ofthe robot, wherein the controller is configured to alter a headingsetting in response to a signal received from the proximity sensorindicating a potential obstacle; a cliff sensor responsive to apotential cliff forward of the robot, wherein the controller isconfigured to alter the heading setting in response to a signal receivedfrom the cliff sensor indicating a potential cliff; a liquid applicatorhoused in the robot body and configured to dispense a liquid onto thecleaning surface while the robot is moving in a direction of forwardtravel of the robot and suspend dispersion of the liquid while moving ina reverse direction of forward travel of the robot; and a squeegeevacuum assembly housed in the robot body and comprising: a squeegeeattached to the robot body and formed with a longitudinal ridge disposedproximate to the cleaning surface and extending across a cleaning widthfor providing a liquid collection zone at a forward edge of the ridge; aliquid collection zone defined by the robot body, the longitudinal ridgecollecting waste liquid within the liquid collection zone as the robotmoves in a forward direction of travel; a vacuum chamber partiallyformed by the squeegee disposed proximate to the longitudinal ridge andextending across the cleaning width, the vacuum chamber in fluidcommunication with the liquid collection zone by a plurality of suctionports defined through the squeegee; and a vacuum for generating anegative air pressure within the vacuum chamber for drawing waste liquidcollection within the liquid collection zone into the vacuum chamber;wherein the cleaning robot has a mass of less than about 10 kg, there isbetween about 1 cm and about 10 cm of cleaning width for every 1 kg ofcleaning robot mass, and the cleaning robot has an average drag force of30-40% of the thrust provided by the drive system.
 2. The surfacetreatment robot of claim 1, further comprising a liquid storage tankcomprising at least one of a waste storage container in fluidcommunication with the vacuum chamber or a cleaning fluid storagecontainer in fluid communication with the liquid applicator.
 3. Thesurface treatment robot of claim 2, wherein the liquid storage tankcomprises both a waste storage container in fluid communication with thevacuum chamber and a cleaning fluid storage container in fluidcommunication with the liquid applicator.
 4. The surface treatment robotof claim 2, wherein the liquid storage tank is removably attached to therobot body.
 5. The surface treatment robot of claim 1, wherein the leftand right drive wheels are positioned along an axis substantiallyperpendicular to a fore-aft axis of the robot.
 6. The surface treatmentrobot of claim 5, wherein the left and right drive wheels are positionedalong an axis offset from a central point of the robot.
 7. The surfacetreatment robot of claim 5, wherein the robot body defines asubstantially circular outer surface, and wherein the drive wheels areconfigured to rotate the robot about a central vertical axis such thatpivoting the robot in place results in the outer surface of the robotmaintaining a substantially constant distance from an obstacle.
 8. Thesurface treatment robot of claim 1, further comprising a user inputcontrol panel disposed on an external surface thereof.
 9. The surfacetreatment robot of claim 1, wherein the liquid applicator is attached tothe robot body as a removably attachable module.
 10. A surface treatmentrobot comprising: a robot body having forward and rear ends; right andleft drive wheels rotatably mounted on the robot body and spaced offsetfrom a transverse axis defined perpendicular to a forward drivedirection of the robot over a cleaning surface; right and left drivemotors coupled to the corresponding drive wheels; a controller incommunication with the drive motor and configured to differentiallysteer the robot and be capable of maneuvering the robot to pivot inplace; a proximity sensor responsive to a potential obstacle forward ofthe robot, wherein the controller is configured to alter a headingsetting in response to a signal received from the proximity sensorindicating a potential obstacle; a cliff sensor responsive to apotential cliff forward of the robot, wherein the controller isconfigured to alter the heading setting in response to a signal receivedfrom the cliff sensor indicating a potential cliff; a first debriscollector comprising: a plenum defined by the robot body and configuredfor sucking debris from the cleaning surface; a waste compartment influid communication with the plenum; and a vacuum blower in fluidcommunication with the plenum and configured to pull debris up throughthe plenum and into the waste compartment; a liquid applicator housed inthe robot body and configured to dispense liquid directly onto thecleaning surface while the robot is moving in a direction of forwardtravel of the robot and suspend dispersion of the liquid while moving ina reverse direction of forward travel of the robot; a second debriscollector comprising: a driven cleaning head rotatably coupled to therobot body; and a bin configured to collect debris removed from thecleaning surface by the cleaning head; and a squeegee vacuum assemblyhoused in the robot body and comprising: a squeegee attached to therobot body and formed with a longitudinal ridge disposed of proximate tothe cleaning surface and extending across a cleaning width for providinga liquid collection zone at a forward edge of the ridge; a liquidcollection zone defined by the robot body, the longitudinal ridgecollecting waste liquid within the liquid collection zone as the robotmoves in a forward direction of travel; and a vacuum chamber partiallyformed by the squeegee disposed proximate to the longitudinal ridge andextending across the cleaning width, the vacuum chamber in fluidcommunication with the liquid collection zone by a plurality of suctionports defined through the squeegee, wherein the vacuum blower generatesa negative air pressure within the vacuum chamber for drawing wasteliquid collected within the liquid collection zone into the vacuumchamber; wherein the cleaning robot has a mass of less than about 10 kg,there is between about 1 cm and about 10 cm of cleaning width for every1 kg of cleaning robot mass, and the cleaning robot has an average dragforce of 30-40% of the thrust provided by the drive wheels.
 11. Thesurface treatment robot of claim 10, further comprising a liquid storagetank comprising at least one of a waste storage container in fluidcommunication with the vacuum chamber or a cleaning fluid storagecontainer in fluid communication with the liquid applicator.
 12. Thesurface treatment robot of claim 11, wherein the liquid storage tankcomprises both a waste storage container in fluid communication with thevacuum chamber and cleaning fluid storage container in fluidcommunication with the liquid applicator.
 13. The surface treatmentrobot of claim 11, wherein the liquid storage tank is removably attachedto the robot body.
 14. The surface treatment robot of claim 10, whereinthe left and right drive wheels are positioned along an axissubstantially perpendicular to a fore-aft axis of the robot.
 15. Thesurface treatment robot of claim 14, wherein the left and right drivewheels are positioned along an axis offset from a central point of therobot.
 16. The surface treatment robot of claim 14, wherein the robotbody defines a substantially circular outer surface, and wherein thedrive wheels are configured to rotate the robot about a central verticalaxis such that pivoting the robot in place results in the outer surfaceof the robot maintaining a substantially constant distance from anobstacle.
 17. The surface treatment robot of claim 10, furthercomprising a user input control panel disposed on an external surfacethereof.
 18. The surface treatment robot of claim 10, wherein the liquidapplicator is attached to the robot body as a removably attachablemodule.